Category Archives: Programming Interview

Given an integer array, one element occurs even number of times and all others have odd occurrences. Find the element with even occurrences.

Given a sorted array of unknown length and a number to search for, return the index of the number in the array. Accessing an element out of bounds throws exception. If the number occurs multiple times, return the index of … Continue reading →

Given two strings, check if they’re anagrams or not. Two strings are anagrams if they are written using the same exact letters, ignoring space, punctuation and capitalization. Each letter should have the same count in both strings. For example, ‘Eleven … Continue reading →

One of the most common string interview questions: Find the first non-repeated (unique) character in a given string.

Given a string of opening and closing parentheses, check whether it’s balanced. We have 3 types of parentheses: round brackets: (), square brackets: [], and curly brackets: {}. Assume that the string doesn’t contain any other character than these, no … Continue reading →

Given a stream of unsorted integers, find the median element in sorted order at any given time. So, we will be receiving a continuous stream of numbers in some random order and we don’t know the stream length in advance. … Continue reading →

This is probably by far the most common string manipulation interview question. Given an input string, reverse all the words. To clarify, input: “Interviews are awesome!” output: “awesome! are Interviews”. Consider all consecutive non-whitespace characters as individual words. If there … Continue reading →

The title says it all, this is a pretty standard interview question. Generate all permutations of a given string.

Given an array of integers find the kth element in the sorted order (not the kth distinct element). So, if the array is [3, 1, 2, 1, 4] and k is 3 then the result is 2, because it’s the … Continue reading →

Given an array: convert it to: in-place using constant extra space.