Arden Dertat

Given an array:

convert it to:

in-place using constant extra space.

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Given a source word, target word and an English dictionary, transform the source word to target by changing/adding/removing 1 character at a time, while all intermediate words being valid English words. Return the transformation chain which has the smallest number of intermediate words.

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This is a very common interview question. Given a binary tree, check whether it’s a binary search tree or not. Simple as that..

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We are given 3 strings: str1, str2, and str3. Str3 is said to be a shuffle of str1 and str2 if it can be formed by interleaving the characters of str1 and str2 in a way that maintains the left to right ordering of the characters from each string. For example, given str1=”abc” and str2=”def”, str3=”dabecf” is a valid shuffle since it preserves the character ordering of the two strings. So, given these 3 strings write a function that detects whether str3 is a valid shuffle of str1 and str2.

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This is a very fundamental question and it’s tricky to implement without any bugs. Given a linkedlist of integers and an integer value, delete every node of the linkedlist containing that value.

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This question can be solved efficiently with a very clever trick. There is an array of non-negative integers. A second array is formed by shuffling the elements of the first array and deleting a random element. Given these two arrays, find which element is missing in the second array. Here is an example input, the first array is shuffled and the number 5 is removed to construct the second array.

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This is one of the most common interview practice questions. Given an array of integers (positive and negative) find the largest continuous sum.

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This is a very elegant question which seems easy at first but requires some hard thinking to solve it efficiently: Given a matrix of integers and coordinates of a rectangular region within the matrix, find the sum of numbers falling inside the rectangle. Our program will be called multiple times with different rectangular regions from the same matrix.

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Once again it’s the college recruiting season of the year and tech companies started the interview process for full time and internship positions. I had many interviews last year these days for a summer internship. Eventually I was an intern at Microsoft Bing, and will be joining there full time next summer. I won’t have any interviews this year, but since most of my friends are actively preparing for them nowadays, I thought it would be useful to share some good quality interview questions and provide my solutions. I come across this particular question pretty often recently: Given an integer array, output all pairs that sum up to a specific value k.

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