Make anagrams from two Strings

Problem Statement Given two strings, find the total number of characters we need to delete from these strings to make them anagrams of each other. Understanding Anagrams Anagrams are defined with respect to a given string of characters (not necessarily characters in the English Alphabet) but a wider set of characters may be. Given two strings A and B, if the number of time each character occurs in both the string is exactly same, we say A and B are anagrams. However, the order in which the character appears may be different and doesn't matter. For example A = axbbxxcecdeedda B = abacb...
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Matrix Rotation and Matrix Transpose

Problem Definition – Matrix Rotation (by 90, 180, 270 degrees) This is a very famous interview question and has been asked numerous times. We are trying to solve the problem of matrix rotations where the inputs are as follows: A matrix of dimension M * N A number from the set (90, 180, ,270) by which we need to rotate the matrix. For simplicity we will consider a matrix to be a 2 dimensional array of integers. What does it mean to rotate a matrix? This can only be explained by nice diagrams. Just for a formal definition, I would say that matrix rotation is a structural re-arrangeme...
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Inorder Predecessor of node in Binary Tree Using Parent Pointer

Introduction This is the seventh article in the Tree Traversals - Online Classes. This article presents ways to find out inorder predecessor of node in binary tree. As we have already read about the Inorder Successor it wont take much effort to understand the predecessor. Definition - Inorder Predecessor of node in Binary Tree If a node K is called the inorder predecessor of node N then N must be visited immediately after K in a inorder traversal of the tree. Below is a more formal definition of Inorder Predecessor: If the node has a left sub-tree, then inorder predecessor is the ...
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Inorder Successor of node in Binary Tree Using Parent Pointer

Introduction This is the sixth article in the Tree Traversals - Online Classes. This article presents ways to find out inorder successor of node in binary tree. Before we jump into the code it would be good to correctly define the meaning of the problem. Definition - Inorder Successor of node in Binary Tree If a node K is called the inorder successor of node N then K must be visited immediately after N in a inorder traversal of the tree. Below is a more formal definition of Inorder Successor: If the node has a right sub-tree, then inorder successor is the left most node of the rig...
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Arrays are permutation of each other

Problem Definition – Arrays are permutation of each other The problem definition goes as follows: Given two arrays of equal length, find out if the elements of one array is the permutation of the elements of another array. Of course the constraint is to solve it in constant space and linear time. Which means that the running time should be O(N) and auxiliary space required should be O(1). Approach There may be several thoughts which seem to work but eventually they will fail at one or the other ways. Here are few interesting ways which may not work for all the conditions: XORing the ...
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Dutch Flag Problem

Problem Definition - Dutch Flag Problem The dutch flag looks like the below image. The problem "Dutch Flag Problem" derives its name from the arrangement of colors in the flag. The actual problem definition goes like this: Given an array of balls of three colors ( Red, White and Blue). The balls are kept in random positions in the array. We need to develop a mechanism which can arrange the balls in groups (based on colors). Below is the image of a possible input and the expected output. The balls of different colors in the above image are randomly distributed in the input where...
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Shift Zeroes To Right

Problem Definition - Shift Zeroes To Right We are trying to solve a problem at hand in which we are given an array of zeroes and positive integers. We need to Shift Zeroes To Right and positive integers to the left without disturbing the relative order of the positive integers. Approach I try to solve the problem in a simple way, you may find a similar problem on the web, here is a approach which solves this problem in O(N) time using constant auxiliary space (may be one or two extra variables). The first thing which comes in mind can be traversing the array and swapping zeroes with the ...
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