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...

# Linked List Cycle

# 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,...