Tinkoff Coding Interview Questions

Min Stack

Design a stack that supports push, pop, top, and retrieving the minimum element in constant time.

Longest Substring Without Repeating Characters

Given a string s, find the length of the longest substring without duplicate characters.

Two Sum

Given an array of integers nums and an integer target, return the indices of the two numbers that add up to target.

Keys and Rooms

There are n rooms labeled from 0 to n - 1 and all the rooms are locked except for room 0. Your goal is to visit all the rooms. However, you cannot enter a locke...

Rotate Image

You are given an n x n 2D matrix representing an image, rotate the image by 90 degrees (clockwise).

Simplify Path

You are given an absolute path for a Unix-style file system, which always begins with a slash '/'. Your task is to transform this absolute path into its simplif...

Backspace String Compare

Given two strings s and t, return true if they are equal when both are typed into empty text editors. '' means a backspace character.

Longest Palindromic Substring

Given a string s, return the longest palindromic substring in s.

Find First and Last Position of Element in Sorted Array

Given an array of integers nums sorted in non-decreasing order, find the starting and ending position of a given target value.

Number of Islands

Given an m x n 2D binary grid grid which represents a map of '1's (land) and '0's (water), return the number of islands.

Search a 2D Matrix

You are given an m x n integer matrix matrix with the following two properties:

Battleships in a Board

Given an m x n matrix board where each cell is a battleship 'X' or empty '.', return the number of the battleships on board.

Form Smallest Number From Two Digit Arrays

Given two arrays of unique digits nums1 and nums2, return the smallest number that contains at least one digit from each array.

Find All Numbers Disappeared in an Array

Given an array nums of n integers where nums[i] is in the range [1, n], return an array of all the integers in the range [1, n] that do not appear in nums.

Longest Subarray of 1's After Deleting One Element

Given a binary array nums, you should delete one element from it.

Minimum Difference Between Highest and Lowest of K Scores

You are given a 0-indexed integer array nums, where nums[i] represents the score of the ith student. You are also given an integer k.

Count Square Submatrices with All Ones

Given a m n matrix of ones and zeros, return how many square submatrices have all ones.

Decode String

Given an encoded string, return its decoded string.

Search in Rotated Sorted Array

There is an integer array nums sorted in ascending order (with distinct values).

Is Subsequence

Given two strings s and t, return true if s is a subsequence of t, or false otherwise.

Event Emitter

Design an EventEmitter class. This interface is similar (but with some differences) to the one found in Node.js or the Event Target interface of the DOM. The Ev...

Department Highest Salary

Table: Employee

Maximize Distance to Closest Person

You are given an array representing a row of seats where seats[i] = 1 represents a person sitting in the ith seat, and seats[i] = 0 represents that the ith seat...

Reverse Linked List

Given the head of a singly linked list, reverse the list, and return the reversed list.

Squares of a Sorted Array

Given an integer array nums sorted in non-decreasing order, return an array of the squares of each number sorted in non-decreasing order.

Isomorphic Strings

Given two strings s and t, determine if they are isomorphic.

Valid Palindrome

A phrase is a palindrome if, after converting all uppercase letters into lowercase letters and removing all non-alphanumeric characters, it reads the same forwa...

Subarray Sums Divisible by K

Given an integer array nums and an integer k, return the number of non-empty subarrays that have a sum divisible by k.

Subarray Sum Equals K

Given an array of integers nums and an integer k, return the total number of subarrays whose sum equals to k.

Find the Longest Balanced Substring of a Binary String

You are given a binary string s consisting only of zeroes and ones.