Category: Yahoo


Dynamic Programming — Longest Palindromic Subsequence

Objective: Given a string, find a longest palindromic subsequence in it. What is Longest Palindromic Subsequence: A longest palindromic subsequence is a sequence that appears in the same relative order, but not necessarily contiguous(not...


Dynamic Programming – Longest Common Subsequence

Objective: Given two string sequences, write an algorithm to find the length of longest subsequence present in both of them. These kind of dynamic programming questions are very famous in the interviews like Amazon,...


Print All N Length Strings from Given Number K

Objective: Given Number K, Print all the strings of N length. Example: N = 2, K = 3 [1, 1] [2, 1] [3, 1] [1, 2] [2, 2] [3, 2] [1, 3] [2, 3]...


Dynamic Programming – Maximum size square sub-matrix with all 1s

Objective: Given a matrix of 0’s and 1’s (binary matrix). Find out Maximum size square sub-matrix with all 1’s. Example: Approach: Base Cases: If only one row is given then cells with 1’s will...


The Word Break Problem

Objective : Given an string and a dictionary of words, find out if the input string can be broken into a space-separated sequence of one or more dictionary words. Example: dictionary = [“I” ,...


Dynamic Programming – Longest Increasing Subsequence

Objective: The longest Increasing Subsequence (LIS) problem is to find the length of the longest subsequence in a given array such that all elements of the subsequence are sorted in increasing order. OR Given...


Backtracking – Search a Word In a Matrix

Objective : Given a 2D matrix of characters. Check whether the word exist in the matrix or not. If it exists then print its path. All movements are allowed (right, left, up, down and...


Dynamic Programming – Minimum Coin Change Problem

Objective: Given a amount ‘A’ and n coins,   v1<v2<v3<………..<vn . Write a program to find out minimum numbers of coins required to make the change for the amount ‘A’. Example: Amount: 5 Coins []...


Find the Deepest Left Node in a Binary Tree.

Objective: – Given a binary tree, Find the deepest left node in it. Approach: This approach is very similar to “Find the Deepest Node in a Binary Tree” with little modification. Take two global...


Print All Paths From Root In a Binary Tree Whose Sum is Equal to a Given Number

Objective: – Given a binary tree and X, write an algorithm to Print all the paths starting from root so that sum of all the nodes in path equals to a given number. Example:


Find the Deepest Node in a Binary Tree.

Objective: – Given a binary tree, write an algorithm to Find the deepest node in it. Approach: Take two global variable as “deepestlevel” and “value“. starting with level=0, Do the inorder traversal and whenever...


Track the Maximum Element in a Stack.

Objective: In a Stack, keep track of maximum value in it. It might be the top element in the stack but once it is poped out, the maximum value should be from the rest...


Print All Possible Valid Combinations Of Parenthesis of Given ‘N’

Objec­tive: – Given “n”, generate all valid parenthesis strings of length “2n”. Example: Given n=2 Output: (()) ()() Approach:


Implement Queue Using Stacks

Objective: We know that Queue is FIFO (First-in-First-Out) and Stack is LIFO ( Last-in-First-Out). Here our objective is to implement queue using stacks. Approach: Take 2 Stacks, stack1 and stack2. stack1 will be used...

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