Problem Given an array of integers nums and an integer target, return indices of the two numbers such that they add up to target. You may assume that each input would have exactly one solution, ...

# Two Sum

# Single Number

Problem Given a non-empty array of integers nums, every element appears twice except for one. Find that single one. You must implement a solution with a linear runtime complexity and use only co...

# Search in Rotated Sorted Array II

Problem There is an integer array nums sorted in non-decreasing order (not necessarily with distinct values). Before being passed to your function, nums is rotated at an unknown pivot index k (0...

# Find Minimum in Rotated Sorted Array

Problem Suppose an array of length n sorted in ascending order is rotated between 1 and n times. For example, the array nums = [0,1,2,4,5,6,7] might become: [4,5,6,7,0,1,2] if it was rotated ...

# Search in Rotated Sorted Array

Problem There is an integer array nums sorted in ascending order (with distinct values). Prior to being passed to your function, nums is possibly rotated at an unknown pivot index k (1 <= k &...

# Search a 2D Matrix

Problem You are given an m x n integer matrix matrix with the following two properties: Each row is sorted in non-decreasing order. The first integer of each row is greater than the last in...

# Guess Number Higher or Lower

Problem We are playing the Guess Game. The game is as follows: I pick a number from 1 to n. You have to guess which number I picked. Every time you guess wrong, I will tell you whether the numb...

# Binary Search

Problem Given an array of integers nums which is sorted in ascending order, and an integer target, write a function to search target in nums. If target exists, then return its index. Otherwise, r...

# Reverse Linked List

Problem Given the head of a singly linked list, reverse the list, and return the reversed list. Examples Example 1: Input: [1,2,3,4,5] Output: [5,4,3,2,1] Example 2: Input: head = [1...

# Add Two Numbers

Problem You are given two non-empty linked lists representing two non-negative integers. The digits are stored in reverse order, and each of their nodes contains a single digit. Add the two numbe...

# Linked List Cycle

Problem Given head, the head of a linked list, determine if the linked list has a cycle in it. There is a cycle in a linked list if there is some node in the list that can be reached again by co...

# Merge k Sorted Lists

Problem You are given an array of k linked-lists lists, each linked-list is sorted in ascending order. Merge all the linked-lists into one sorted linked-list and return it. Examples Example 1...

# Shortest Subarray with Sum at Least K

Problem Given an integer array nums and an integer k, return the length of the shortest non-empty subarray of nums with a sum of at least k. If there is no such subarray, return -1. A subarray i...

# Smallest Rotation with Highest Score

Problem You are given an array nums. You can rotate it by a non-negative integer k so that the array becomes [nums[k], nums[k + 1], ... nums[nums.length - 1], nums[0], nums[1], ..., nums[k-1]]. A...

# Subarray Sum Equals K

Problem Given an array of integers nums and an integer k, return the total number of subarrays whose sum equals to k. A subarray is a contiguous non-empty sequence of elements within an array. ...

# Continuous Subarray Sum

Problem Given an integer array nums and an integer k, return true if nums has a good subarray or false otherwise. A good subarray is a subarray where: its length is at least two, and the s...

# Max Sum of Rectangle No Larger Than K

Problem Given an m x n matrix matrix and an integer k, return the max sum of a rectangle in the matrix such that its sum is no larger than k. It is guaranteed that there will be a rectangle with...

# Range Sum Query 2D - Immutable

Problem Given a 2D matrix matrix, handle multiple queries of the following type: Calculate the sum of the elements of matrix inside the rectangle defined by its upper left corner (row1, col1)...

# Range Sum Query - Immutable

Problem Given an integer array nums, handle multiple queries of the following type: Calculate the sum of the elements of nums between indices left and right inclusive where left <= right. Im...

# Product of Array Except Self

Problem Given an integer array nums, return an array answer such that answer[i] is equal to the product of all the elements of nums except nums[i]. The product of any prefix or suffix of nums is...

# Minimum Size Subarray Sum

Problem Given an array of positive integers nums and a positive integer target, return the minimal length of a subarray whose sum is greater than or equal to target. If there is no such subarray,...