Hill climbing algorithm in artificial intelligence with example ppt - CSCI 5582 Artificial Intelligence. CS 2710, ISSP 2610 R&N Chapter 4.1 Local Search and Optimization * Example Local Search Problem Formulation Group travel: people traveling from different places: See chapter4example.txt on the course schedule. From Segaran, T. Programming Collective Intelligence, O’Reilly, 2007.

 
May 15, 2023 · Here’s the pseudocode for the best first search algorithm: 4. Comparison of Hill Climbing and Best First Search. The two algorithms have a lot in common, so their advantages and disadvantages are somewhat similar. For instance, neither is guaranteed to find the optimal solution. For hill climbing, this happens by getting stuck in the local ... . Homes for rent under dollar1000

In Artificial Intelligence, Search techniques are universal problem-solving methods. Rational agents or Problem-solving agents in AI mostly used these search strategies or algorithms to solve a specific problem and provide the best result. Problem-solving agents are the goal-based agents and use atomic representation.Hill-climbing (or gradient ascent/descent) \Like climbing Everest in thick fog with amnesia" function Hill-Climbing(problem) returns a state that is a local maximum inputs: problem, a problem local variables: current, a node neighbor, a node current Make-Node(Initial-State[problem]) loop do neighbor a highest-valued successor of currentTitle: Hill-climbing Search 1 Hill-climbing Search. Goal Optimizing an objective function. Can be applied to goal predicate type of problems. BSAT with objective function number of clauses satisfied. Intuition Always move to a better state ; 2 Some Hill-Climbing Algos. Start State empty state or random state or special state ; Until (no ...Breadth First Search Ravi Kumar B N, Asst.Prof,CSE,BMSIT 27. Breadth First Search Algorithm: 1. Create a variable called NODE-LIST and set it to initial state 2. Until a goal state is found or NODE-LIST is empty do a. Remove the first element from NODE-LIST and call it E. If NODE- LIST was empty, quit b.Such a technique is called Means-Ends Analysis. Means-Ends Analysis is problem-solving techniques used in Artificial intelligence for limiting search in AI programs. It is a mixture of Backward and forward search technique. The MEA technique was first introduced in 1961 by Allen Newell, and Herbert A. Simon in their problem-solving computer ...Mohammad Faizan Follow Recommended Heuristc Search Techniques Jismy .K.Jose 9.6K views•49 slides Hill climbing algorithm in artificial intelligence sandeep54552 4.7K views•7 slides Control Strategies in AI Amey Kerkar 28.6K views•76 slides Hill climbing algorithm Dr. C.V. Suresh Babu 2.4K views•14 slidesBeam Search : A heuristic search algorithm that examines a graph by extending the most promising node in a limited set is known as beam search. Beam search is a heuristic search technique that always expands the W number of the best nodes at each level. It progresses level by level and moves downwards only from the best W nodes at each level.ICS 171 Fall 2006 Summary Heuristics and Optimal search strategies heuristics hill-climbing algorithms Best-First search A*: optimal search using heuristics Properties of A* admissibility, monotonicity, accuracy and dominance efficiency of A* Branch and Bound Iterative deepening A* Automatic generation of heuristics Problem: finding a Minimum Cost Path Previously we wanted an arbitrary path to ...Step1: Generate possible solutions. Step2: Evaluate to see if this is the expected solution. Step3: If the solution has been found quit else go back to step 1. Hill climbing takes the feedback from the test procedure and the generator uses it in deciding the next move in the search space.For example, the travelling salesman problem, the eight-queens problem, circuit design, and a variety of other real-world problems. Hill Climbing has been used in inductive learning models. One such example is PALO, a probabilistic hill climbing system which models inductive and speed-up learning.Title: Hill-climbing Search 1 Hill-climbing Search. Goal Optimizing an objective function. Can be applied to goal predicate type of problems. BSAT with objective function number of clauses satisfied. Intuition Always move to a better state ; 2 Some Hill-Climbing Algos. Start State empty state or random state or special state ; Until (no ...Following are the types of hill climbing in artificial intelligence: 1. Simple Hill Climbing. One of the simplest approaches is straightforward hill climbing. It carries out an evaluation by examining each neighbor node's state one at a time, considering the current cost, and announcing its current state.A* search. Renas R. Rekany Artificial Intelligence Nawroz University Keep Reading as long as you breathComSci: Renas R. Rekany Oct2016 5 Hill Climbing • Hill climbing search algorithm (also known as greedy local search) uses a loop that continually moves in the direction of increasing values (that is uphill).* Simple Hill Climbing Example: coloured blocks Heuristic function: the sum of the number of different colours on each of the four sides (solution = 16). * Steepest-Ascent Hill Climbing (Gradient Search) Considers all the moves from the current state. Selects the best one as the next state.Beam Search : A heuristic search algorithm that examines a graph by extending the most promising node in a limited set is known as beam search. Beam search is a heuristic search technique that always expands the W number of the best nodes at each level. It progresses level by level and moves downwards only from the best W nodes at each level.Dec 21, 2021 · A* Algorithm maintains a tree of paths originating at the initial state. 2. It extends those paths one edge at a time. 3. It continues until final state is reached. Example Example Example Example Example Pros & Cons Pros: It is complete and optimal. It is the best one from other techniques. It is used to solve very complex problems. It is ... INTRODUCTION Hill Climbing is a heuristic search that tries to find a sufficiently good solution to the problem, according to its current position. Types of Hill climbing: • Simple Hill climbing: select first node that is closer to the solution state than current node. • Steepest-Ascent Hill climbing: examines all nodes then selects closest ...A sufficiently good solution to the desired function, given sufficient training data goal from the state!: when reaching a plateau, jump somewhere hill climbing algorithm in artificial intelligence with example ppt and restart the algorithm, the algorithm with. Is a heuristic search Puzzle problem in AI ( Artificial Intelligence...Breadth First Search Ravi Kumar B N, Asst.Prof,CSE,BMSIT 27. Breadth First Search Algorithm: 1. Create a variable called NODE-LIST and set it to initial state 2. Until a goal state is found or NODE-LIST is empty do a. Remove the first element from NODE-LIST and call it E. If NODE- LIST was empty, quit b.Abstract: The paper proposes artificial intelligence technique called hill climbing to find numerical solutions of Diophantine Equations. Such equations are important as they have many applications in fields like public key cryptography, integer factorization, algebraic curves, projective curves and data dependency in super computers. This information can be in the form of heuristics, estimates of cost, or other relevant data to prioritize which states to expand and explore. Examples of informed search algorithms include A* search, Best-First search, and Greedy search. Example: Greedy Search and Graph Search. Here are some key features of informed search algorithms in AI:1. one of the problems with hill climbing is getting stuck at the local minima & this is what happens when you reach F. An improved version of hill climbing (which is actually used practically) is to restart the whole process by selecting a random node in the search tree & again continue towards finding an optimal solution.Hill-climbing (or gradient ascent/descent) \Like climbing Everest in thick fog with amnesia" function Hill-Climbing(problem) returns a state that is a local maximum inputs: problem, a problem local variables: current, a node neighbor, a node current Make-Node(Initial-State[problem]) loop do neighbor a highest-valued successor of current Hill-climbing Search The successor function is where the intelligence lies in hill-climbing search It has to be conservative enough to preserve significant “good” portions of the current solution And liberal enough to allow the state space to be preserved without degenerating into a random walk Hill-climbing search Problem: depending on ... hill climbing algorithm with examples#HillClimbing#AI#ArtificialIntelligenceBreadth First Search Ravi Kumar B N, Asst.Prof,CSE,BMSIT 27. Breadth First Search Algorithm: 1. Create a variable called NODE-LIST and set it to initial state 2. Until a goal state is found or NODE-LIST is empty do a. Remove the first element from NODE-LIST and call it E. If NODE- LIST was empty, quit b.This information can be in the form of heuristics, estimates of cost, or other relevant data to prioritize which states to expand and explore. Examples of informed search algorithms include A* search, Best-First search, and Greedy search. Example: Greedy Search and Graph Search. Here are some key features of informed search algorithms in AI:Mar 25, 2018 · In the depth-first search, the test function will merely accept or reject a solution. But in hill climbing the test function is provided with a heuristic function which provides an estimate of how close a given state is to goal state. The hill climbing test procedure is as follows : 1. Mohammad Faizan Follow Recommended Heuristc Search Techniques Jismy .K.Jose 9.6K views•49 slides Hill climbing algorithm in artificial intelligence sandeep54552 4.7K views•7 slides Control Strategies in AI Amey Kerkar 28.6K views•76 slides Hill climbing algorithm Dr. C.V. Suresh Babu 2.4K views•14 slidesMay 18, 2015 · Mohammad Faizan Follow Recommended Heuristc Search Techniques Jismy .K.Jose 9.6K views•49 slides Hill climbing algorithm in artificial intelligence sandeep54552 4.7K views•7 slides Control Strategies in AI Amey Kerkar 28.6K views•76 slides Hill climbing algorithm Dr. C.V. Suresh Babu 2.4K views•14 slides Stochastic Hill climbing is an optimization algorithm. It makes use of randomness as part of the search process. This makes the algorithm appropriate for nonlinear objective functions where other local search algorithms do not operate well. It is also a local search algorithm, meaning that it modifies a single solution and searches the ...Hill-climbing Search The successor function is where the intelligence lies in hill-climbing search It has to be conservative enough to preserve significant “good” portions of the current solution And liberal enough to allow the state space to be preserved without degenerating into a random walk Hill-climbing search Problem: depending on ...Aug 2, 2023 · Following are the types of hill climbing in artificial intelligence: 1. Simple Hill Climbing. One of the simplest approaches is straightforward hill climbing. It carries out an evaluation by examining each neighbor node's state one at a time, considering the current cost, and announcing its current state. Can’t see past a single move in the state space. Simple Hill Climbing Example TSP - define state space as the set of all possible tours. Operators exchange the position of adjacent cities within the current tour. Heuristic function is the length of a tour. TSP Hill Climb State Space Steepest-Ascent Hill Climbing A variation on simple hill ...Beam Search : A heuristic search algorithm that examines a graph by extending the most promising node in a limited set is known as beam search. Beam search is a heuristic search technique that always expands the W number of the best nodes at each level. It progresses level by level and moves downwards only from the best W nodes at each level.4. Uniform-cost Search Algorithm: Uniform-cost search is a searching algorithm used for traversing a weighted tree or graph. This algorithm comes into play when a different cost is available for each edge. The primary goal of the uniform-cost search is to find a path to the goal node which has the lowest cumulative cost. Hill-Climbing Search. It is an iterative algorithm that starts with an arbitrary solution to a problem and attempts to find a better solution by changing a single element of the solution incrementally. If the change produces a better solution, an incremental change is taken as a new solution.• Steepest ascent, hill-climbing with limited sideways moves, stochastic hill-climbing, first-choice hill-climbing are all incomplete. • Complete: A local search algorithm is complete if it always finds a goal if one exists. • Optimal: A local search algorithm is complete if it always finds the global maximum/minimum.Disadvantages: The question that remains on hill climbing search is whether this hill is the highest hill possible. Unfortunately without further extensive exploration, this question cannot be answered. This technique works but as it uses local information that’s why it can be fooled. The algorithm doesn’t maintain a search tree, so the ... Hill Climbing Algorithm: Hill climbing search is a local search problem. The purpose of the hill climbing search is to climb a hill and reach the topmost peak/ point of that hill. It is based on the heuristic search technique where the person who is climbing up on the hill estimates the direction which will lead him to the highest peak.Artificial Intelligence Methods Graham Kendall Hill Climbing Hill Climbing Hill Climbing - Algorithm 1. Pick a random point in the search space 2. Consider all the neighbours of the current state 3. Choose the neighbour with the best quality and move to that state 4. Repeat 2 thru 4 until all the neighbouring states are of lower quality 5. Beam Search is a greedy search algorithm similar to Breadth-First Search (BFS) and Best First Search (BeFS). In fact, we’ll see that the two algorithms are special cases of the beam search. Let’s assume that we have a Graph that we want to traverse to reach a specific node. We start with the root node.hill climbing search algorithm1 hill climbing algorithm evaluate initial state, if its goal state quit, otherwise make current state as initial state2 select...Ex:- Some games like chess, hill climbing, certain design and scheduling problems. Figure 5: AI Search Algorithms Classification (Image designed by Author ) Search algorithm evaluating criteria:First, let's talk about the Hill climbing in Artificial intelligence. Hill Climbing Algorithm. It is a technique for optimizing the mathematical problems. Hill Climbing is widely used when a good heuristic is available. It is a local search algorithm that continuously moves in the direction of increasing elevation/value to find the mountain's ...For example, the travelling salesman problem, the eight-queens problem, circuit design, and a variety of other real-world problems. Hill Climbing has been used in inductive learning models. One such example is PALO, a probabilistic hill climbing system which models inductive and speed-up learning.First, let's talk about the Hill climbing in Artificial intelligence. Hill Climbing Algorithm. It is a technique for optimizing the mathematical problems. Hill Climbing is widely used when a good heuristic is available. It is a local search algorithm that continuously moves in the direction of increasing elevation/value to find the mountain's ...move. For example, we could try 3-opt, rather than a 2-opt move when implementing the TSP. Unfortunately, neither of these have proved satisfactory in practice when using a simple hill climbing algorithm. Simulated annealing solves this problem by allowing worse moves (lesser quality) to be taken some of the time.Dec 16, 2019 · 👉Subscribe to our new channel:https://www.youtube.com/@varunainashots 🔗Link for AI notes: https://rb.gy/9kj1z👩‍🎓Contributed by: Nisha GuptaThe best first... Beam Search : A heuristic search algorithm that examines a graph by extending the most promising node in a limited set is known as beam search. Beam search is a heuristic search technique that always expands the W number of the best nodes at each level. It progresses level by level and moves downwards only from the best W nodes at each level.Hill Climbing. Hill climbing is one type of a local search algorithm. In this algorithm, the neighbor states are compared to the current state, and if any of them is better, we change the current node from the current state to that neighbor state.May 15, 2023 · Here’s the pseudocode for the best first search algorithm: 4. Comparison of Hill Climbing and Best First Search. The two algorithms have a lot in common, so their advantages and disadvantages are somewhat similar. For instance, neither is guaranteed to find the optimal solution. For hill climbing, this happens by getting stuck in the local ... Following are the types of hill climbing in artificial intelligence: 1. Simple Hill Climbing. One of the simplest approaches is straightforward hill climbing. It carries out an evaluation by examining each neighbor node's state one at a time, considering the current cost, and announcing its current state.Greedy search example Arad (366) 6 februari Pag. 2008 7 AI 1 Assume that we want to use greedy search to solve the problem of travelling from Arad to Bucharest. The initial state=Arad Greedy search example Arad Sibiu(253) Zerind(374) Pag. 2008 8 AI 1 The first expansion step produces: – Sibiu, Timisoara and Zerind Greedy best-first will ... INTRODUCTION Hill Climbing is a heuristic search that tries to find a sufficiently good solution to the problem, according to its current position. Types of Hill climbing: • Simple Hill climbing: select first node that is closer to the solution state than current node. • Steepest-Ascent Hill climbing: examines all nodes then selects closest ...CSCI 5582 Artificial Intelligence. CS 2710, ISSP 2610 R&N Chapter 4.1 Local Search and Optimization * Example Local Search Problem Formulation Group travel: people traveling from different places: See chapter4example.txt on the course schedule. From Segaran, T. Programming Collective Intelligence, O’Reilly, 2007. Feb 8, 2022 · Ex:- Some games like chess, hill climbing, certain design and scheduling problems. Figure 5: AI Search Algorithms Classification (Image designed by Author ) Search algorithm evaluating criteria: Jan 28, 2022 · Hill Climbing Search Solved Example using Local and Global Heuristic Function by Dr. Mahesh HuddarThe following concepts are discussed:_____... Mar 28, 2023 · Introduction to Hill Climbing Algorithm. Hill Climbing is a self-discovery and learns algorithm used in artificial intelligence algorithms. Once the model is built, the next task is to evaluate and optimize it. Hill climbing is one of the optimization techniques which is used in artificial intelligence and is used to find local maxima. Hill climbing. A surface with only one maximum. Hill-climbing techniques are well-suited for optimizing over such surfaces, and will converge to the global maximum. In numerical analysis, hill climbing is a mathematical optimization technique which belongs to the family of local search. It is an iterative algorithm that starts with an arbitrary ...Jan 27, 2018 · The application of the hill- climbing algorithm to a tree that has been generated prior to the search is illustrated in Figure 11.1. State Space Representation and Search Page 17 Figure 11.1 The hill-climbing algorithm is described below. The hill-climbing algorithm generates a partial tree/graph. Let's take an example of two-player search tree to understand the working of Alpha-beta pruning. Step 1: At the first step the, Max player will start first move from node A where α= -∞ and β= +∞, these value of alpha and beta passed down to node B where again α= -∞ and β= +∞, and Node B passes the same value to its child D. Following are the types of hill climbing in artificial intelligence: 1. Simple Hill Climbing. One of the simplest approaches is straightforward hill climbing. It carries out an evaluation by examining each neighbor node's state one at a time, considering the current cost, and announcing its current state.A class of general purpose algorithms that operates in a brute force way The search space is explored without leveraging on any information on the problem Also called blind search, or naïve search Since the methods are generic they are intrinsically inefficient E.g. Random Search For example in Artificial Intelligence Program DENDRAL we make use of two techniques, the first one is Constraint Satisfaction Techniques followed by Generate and Test Procedure to work on reduced search space i.e. yield an effective result by working on a lesser number of lists generated in the very first step. AlgorithmHill-climbing Search >> Drawbacks Hill-climbing search often gets stuck for the following reasons: Local Maxima >> It is a peak that is higher than each of its neighboring states but lower than the global maximum. For 8-queens problem at local minima, each move of a single queen makes the situation worse. Ridges >> Sequence of local maxima ...Sep 8, 2019 · Algorithm for Simple Hill Climbing: Step 1: Evaluate the initial state, if it is goal state then return success and Stop. Step 2: Loop Until a solution is found or there is no new operator left to ... Example 1 Apply the hill climbing algorithm to solve the blocks world problem shown in Figure. Solution To use the hill climbing algorithm we need an evaluation function or a heuristic function.There are several variations of Hill Climbing, including steepest ascent Hill Climbing, first-choice Hill Climbing, and simulated annealing. In steepest ascent Hill Climbing, the algorithm evaluates all the possible moves from the current solution and selects the one that leads to the best improvement.Hill climbing is basically a search technique or informed search technique having different weights based on real numbers assigned to different nodes, branches, and goals in a path. In AI, machine learning, deep learning, and machine vision, the algorithm is the most important subset. With the help of these algorithms, ( What Are Artificial ...Say the hidden function is: f (x,y) = 2 if x> 9 & y>9. f (x,y) = 1 if x>9 or y>9 f (x,y) = 0 otherwise. GA Works Well here. Individual = point = (x,y) Mating: something from each so: mate ( {x,y}, {x’,y’}) is {x,y’} and {x’,y}. No mutation Hill-climbing does poorly, GA does well.Mohammad Faizan Follow Recommended Heuristc Search Techniques Jismy .K.Jose 9.6K views•49 slides Hill climbing algorithm in artificial intelligence sandeep54552 4.7K views•7 slides Control Strategies in AI Amey Kerkar 28.6K views•76 slides Hill climbing algorithm Dr. C.V. Suresh Babu 2.4K views•14 slidesHill-climbing (or gradient ascent/descent) \Like climbing Everest in thick fog with amnesia" function Hill-Climbing(problem) returns a state that is a local maximum inputs: problem, a problem local variables: current, a node neighbor, a node current Make-Node(Initial-State[problem]) loop do neighbor a highest-valued successor of currentIn the depth-first search, the test function will merely accept or reject a solution. But in hill climbing the test function is provided with a heuristic function which provides an estimate of how close a given state is to goal state. The hill climbing test procedure is as follows : 1.Local search algorithms • Hill-climbing search – Gradient descent in continuous state spaces – Can use, e.g., Newton’s method to find roots • Simulated annealing search • Local beam search • Genetic algorithms • Linear Programming (for specialized problems)Introduction HillHill climbingclimbing. Artificial Intelligence search algorithms Search techniques are general problem-solving methods. When there is a formulated search problem, a set of states, a set of operators, an initial state, and a goal criterion we can use search techniques to solve the problem (Pearl & Korf, 1987)There are mainly four ways of knowledge representation which are given as follows: Logical Representation. Semantic Network Representation. Frame Representation. Production Rules. 1. Logical Representation. Logical representation is a language with some concrete rules which deals with propositions and has no ambiguity in representation. Aug 28, 2018 · Breadth First Search Ravi Kumar B N, Asst.Prof,CSE,BMSIT 27. Breadth First Search Algorithm: 1. Create a variable called NODE-LIST and set it to initial state 2. Until a goal state is found or NODE-LIST is empty do a. Remove the first element from NODE-LIST and call it E. If NODE- LIST was empty, quit b. Best first search algorithm: Step 1: Place the starting node into the OPEN list. Step 2: If the OPEN list is empty, Stop and return failure. Step 3: Remove the node n, from the OPEN list which has the lowest value of h (n), and places it in the CLOSED list. Step 4: Expand the node n, and generate the successors of node n. Sep 8, 2019 · Algorithm for Simple Hill Climbing: Step 1: Evaluate the initial state, if it is goal state then return success and Stop. Step 2: Loop Until a solution is found or there is no new operator left to ...

Best first search algorithm: Step 1: Place the starting node into the OPEN list. Step 2: If the OPEN list is empty, Stop and return failure. Step 3: Remove the node n, from the OPEN list which has the lowest value of h (n), and places it in the CLOSED list. Step 4: Expand the node n, and generate the successors of node n.. Sdn do 2022 2023

hill climbing algorithm in artificial intelligence with example ppt

Step1: Generate possible solutions. Step2: Evaluate to see if this is the expected solution. Step3: If the solution has been found quit else go back to step 1. Hill climbing takes the feedback from the test procedure and the generator uses it in deciding the next move in the search space.There are mainly four ways of knowledge representation which are given as follows: Logical Representation. Semantic Network Representation. Frame Representation. Production Rules. 1. Logical Representation. Logical representation is a language with some concrete rules which deals with propositions and has no ambiguity in representation. In this video we will talk about local search method and discuss one search algorithm hill climbing which belongs to local search method. We will also discus...Hill climbing algorithm is one such optimization algorithm used in the field of Artificial Intelligence. It is a mathematical method which optimizes only the neighboring points and is considered to be heuristic. A heuristic method is one of those methods which does not guarantee the best optimal solution. This algorithm belongs to the local ...Artificial Intelligence Methods Graham Kendall Hill Climbing Hill Climbing Hill Climbing - Algorithm 1. Pick a random point in the search space 2. Consider all the neighbours of the current state 3. Choose the neighbour with the best quality and move to that state 4. Repeat 2 thru 4 until all the neighbouring states are of lower quality 5. Stochastic Hill climbing is an optimization algorithm. It makes use of randomness as part of the search process. This makes the algorithm appropriate for nonlinear objective functions where other local search algorithms do not operate well. It is also a local search algorithm, meaning that it modifies a single solution and searches the ...Artificial Intelligence is the study of building agents that act rationally. Most of the time, these agents perform some kind of search algorithm in the background in order to achieve their tasks. A search problem consists of: A State Space. Set of all possible states where you can be. A Start State.Feb 8, 2022 · Ex:- Some games like chess, hill climbing, certain design and scheduling problems. Figure 5: AI Search Algorithms Classification (Image designed by Author ) Search algorithm evaluating criteria: Courses. Artificial Intelligence (AI) refers to the simulation of human intelligence in machines that are programmed to think and act like humans. It involves the development of algorithms and computer programs that can perform tasks that typically require human intelligence such as visual perception, speech recognition, decision-making, and ...Hill climbing algorithm is a local search algorithm that continuously moves in the direction of increasing elevation/value to find the peak of the mountain o...Hill-climbing (or gradient ascent/descent) function Hill-Climbing (problem) returns a state that is a local maximum inputs: problem, a problem local variables: current, a node neighbor, a node current Make-Node(problem.Initial-State) loop do neighbor a highest-valued successor of current if neighbor.Value current.Value then return current.StateICS 171 Fall 2006 Summary Heuristics and Optimal search strategies heuristics hill-climbing algorithms Best-First search A*: optimal search using heuristics Properties of A* admissibility, monotonicity, accuracy and dominance efficiency of A* Branch and Bound Iterative deepening A* Automatic generation of heuristics Problem: finding a Minimum Cost Path Previously we wanted an arbitrary path to ...See full list on cs50.harvard.edu Aug 28, 2018 · Breadth First Search Ravi Kumar B N, Asst.Prof,CSE,BMSIT 27. Breadth First Search Algorithm: 1. Create a variable called NODE-LIST and set it to initial state 2. Until a goal state is found or NODE-LIST is empty do a. Remove the first element from NODE-LIST and call it E. If NODE- LIST was empty, quit b. .

Popular Topics