String Algorithm: Reverse the first k characters for every 2k characters
Given a string and an integer k, you need to reverse the first k characters for every 2k characters counting from the start of the string. If there are …
How to Generate Parentheses using Bruteforce or Depth First Search (Backtracking) Algorithms?
Given n pairs of parentheses, write a function to generate all combinations of well-formed parentheses. For example, given n = 3, a solution set is: We can use the …
Algorithm to Construct Binary Tree from Preorder and Inorder Traversal
Given preorder and inorder traversal of a tree, construct the binary tree. You may assume that duplicates do not exist in the tree. For example, given preorder = inorder …
The 24 Game Algorithm using Depth First Search
You have 4 cards each containing a number from 1 to 9. You need to judge whether they could operated through *, /, +, -, (, ) to get …
How to Count the Path Sum from a Binary Tree using Depth First Search Algorithm?
You are given a binary tree in which each node contains an integer value. Find the number of paths that sum to a given value. The path does not …
How to Multiply Two Matrices in C++?
Given two sparse matrices A and B, return the result of AB. You may assume that A’s column number is equal to B’s row number. Example: Input: A = …