Sort an array of 0s, 1s and 2s || Dutch National Flag solution

[Question]: How to sort an array which has 0s, 1s and 2s Approach #1 Using Dutch National Flag I used three pointers low mid & high The sorting of 0,1,2 is as per below steps arr[0….low-1] contains 0. [most left part] arr[low….mid-1] contains 1arr[high+1….n-1] contains 2. [most right part],So we swap according to the left(0) […]

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Two Sum Problem

[Question] : Given an array of integers nums and an integer target, find indices of the two numbers which addition equals to target.Example: Input: nums = [2,7,11,15], target = 13 Output: [0,2] Explanation: Because nums[0] + nums[2] == 13, we return [0, 2]. Approach #1 : Using Two pointers: – Step 1: First sort array thenStep 2: If arr[left]

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How to Find a number which appears once and other numbers are twice ?

[Question]: In a given random array find a number which appears only single time Example : Random array input – [9,2,2,3,4,4,3] output = 9Solution: Step 1: Create a dictionary. Step 2: Create loop and fill the keys with element occurrence.Step 3: Create a loop and return the dictionary element which has only single occurrence .T

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