backtracking

Wikipedia about Depth First Search: Depth-first search (DFS) is an algorithm for traversing or searching a tree, tree structure, or graph. One starts at the root (selecting some node as the root in the graph case) and explores as far as possible along each branch before backtracking. So what is Breadth First Search? "an algorithm that choose a starting node, checks all nodes backtracks , chooses the shortest path, chose neighbour nodes backtracks , chose the shortest path, finally finds the optimal path because of traversing each path due to continuous backtracking. Regex find 's pruning --

What is the difference between backtracking and recursion ? How this program is working ? void generate_all(int n) { if(n<1) printf("%s\n", ar); else{ ar[n-1]='0'; //fix (n)th bit as '0' generate_all(n-1); //generate all combinations for other n-1 positions. ar[n-1]='1'; //fix (n)th bit as '1' generate_all(n-1); //generate all combinations for other n-1 positions. } vivoconunxino That question is like asking what's the difference between a car and a DeLorean . In recursion function calls itself until reaches a base case. In backtracking you use recursion in order to explore all the

Im having troubles trying to resolve the Knapsack problem using backtraking. For example, for the following values, the Knapsack function will return 14 as the solution, but the correct result should be 7. int n = 3, weights[] = {2, 3, 1}, values[] = {6, 15, 7}; int solution = 0, max = 2; void Knapsack (int i, int max, int value, int *solution) { int k; for (k = i; k < n; k++) { if (weights[k] <= max) { Knapsack (k, max - weights[k], value + values[k], solution); if (value+ values[k] > *solution) *solution= value + values[k]; } } } What is the problem here? #include<iostream> #include<vector>

The following expression: ^(#ifdef FEATURE)+?\s*$((\r\n.*?)*^(#endif)+\s*[\/\/]*\s*(end of)*\s*FEATURE)+?$ Overrides the matching buffer when running my compiled .Jar file. The matching string can be similar to: this is a junk line #ifdef FEATURE #endif // end of FEATURE this is a junk line #ifdef FEATURE this is a junk line that should be matched: HOLasduiqwhei & // FEATURE fjfefj #endif // h #endif FEATURE this is a junk line So, the bold strings should match. The error is as follows: at java.util.regex.Pattern$GroupHead.match(Unknown Source) at java.util.regex.Pattern$Loop.match(Unknown

I'm struggling with a backtracking algorithm to determine wether a Sudoku has a unique solution or if it has multiple Solutions. Here's the backtracking code i use: static boolean solve(int i, int j, int[][] cells) { if (i == 9) { i = 0; if (++j == 9) return true; } if (cells[i][j] != 0) // skip filled cells return solve(i+1,j,cells); for (int val = 1; val <= 9; ++val) { if (legal(i,j,val,cells)) { cells[i][j] = val; if (solve(i+1,j,cells)) return true; } } cells[i][j] = 0; // reset on backtrack return false; } First approach: If i change for (int val = 1; val <= 9; ++val) { for (int val = 9;

You need to climb a staircase that has n steps, and you decide to get some extra exercise by jumping up the steps. You can cover at most k steps in a single jump. Return all the possible sequences of jumps that you could take to climb the staircase, sorted. My implementation is obviously giving me the wrong answer. def climbingStaircase(n, k): final_res=[] final_res.append(CSR(n,k,[])) return final_res def CSR(n,k,res): if n == 0: return res else: for i in range(1,k+1): if n-i>=0: res.append(i) n=n-i res=CSR(n,i,res) return res For n = 4 and k = 2, the output should be [[1, 1, 1, 1], [1, 1, 2]

I'm trying to solve the knight's tour problem using backtracking. I think the algorithm I have should work. I've tried but I can't figure out why it isn't working. It results in an infinite loop. However if I comment out the line that back track solutionBoard[dst.x][dst.y]=-1; it works! I just don't understand why! Any help would be appreciated. private int solutionBoard[][] = new int [8][8]; // The eight possible moves a knight can make from any given position private static final Point[] MOVES = new Point[] { new Point(-2, -1), new Point(-2, 1), new Point(2, -1), new Point(2, 1), new Point(