Find departure and destination cities from the itinerary

You are on a business trip and traveling from one city to another. you have a stack of unsorted flight boarding passes. The only departure city and destination city are on the boarding pass. how do you find the first departure city and your final destination city, Example:  [Dallas, Austin], [Houston, Dallas], [Austin, Seattle] Output: … Read more

Decimal to Binary

Given a decimal number, convert that number to its binary representation. Example:  Number: 5, binary representation: 101 Number: 8, binary representation: 1000 Number: 105, binary representation: 1101001 Solution:  Initialize a result string and while the given number is greater than 0, keep dividing it by 2 and append the remainder of division to the result … Read more

Maximum Consecutive Ones

Given a binary array (contains only 0’s and 1’s), find out the number of maximum consecutive ones.  Example: Input: [0, 1, 1, 0, 1, 1, 1, 1, 0, 0, 1] Max consecutive ones: 4 Input: [0, 1, 1, 0, 1, 1], Max consecutive ones: 2 Input: [0, 0, 0, 0] Max consecutive ones: 0 Solution: … Read more

Duplicate even elements in an array

Given an array of numbers, write a program to duplicate the even numbers and return the new array. Example: Input: [2, 4, 1, 5, 2, 3, 8, 9, 10, 4] Output: [2, 2, 4, 4, 1, 5, 2, 2, 3, 8, 8, 9, 10, 10, 4, 4] Input: [2, 4, 6, 8] Output: [2, 2, … Read more

Find the number of pairs with odd XOR

Given an array of integers, write a program to find the number of pairs for which the XOR is an odd number. Example: Input[] = {3, 2, 1} Output: 2 Note: 1 XOR 2 = 3 and 2 XOR 3 = 1 Input[] = {3, 6, 9, 4} Output: 4 Naive Approach: Use nested loops … Read more

Remove Duplicates from Sorted Array

Given a sorted array of integers, write a program to remove duplicates in-place by modifying the given array such that all unique integers will be at the beginning of the array, and do not worry about other indexes after the new length. Example: Given Input: [1, 1, 2, 3, 3] Output: [1, 2, 3, 3, … Read more

Replace Elements with Greatest Element on Right

Given an array of numbers nums[], write ment a function to replace each element of the array with the greatest element present to its right side. Replace the last element with -1.  Example: Input: [4, 5, 2, 25, 13, 16, 8] Output: [25, 25, 25, 16, 16, 8, -1] Input: [4, 5, 2, 25, 13, … Read more