Given an m x n binary matrix filled with 0’s and 1’s, find the largest square containing only 1’s and return its area.
Given an integer array nums, return true if any value appears at least twice in the array, and return false if every element is distinct.
You are given an integer array nums and two integers indexDiff and valueDiff. Find a pair of indices (i, j) such that: i != j, abs(i – j) <= indexDiff. abs(nums[i] - nums[j]) <= valueDiff, and Return true if such pair exists or false otherwise.
Given a string s which represents an expression, evaluate this expression and return its value. The integer division should truncate toward zero.
Given a string s, return the longest palindromic substring in s. A palindrome is a string which reads the same in both directions. For example, S = “aba” is a palindrome, S = “abc” is not.
Given an integer array nums, return all the triplets [nums[i], nums[j], nums[k]] such that i != j, i != k, and j != k, and nums[i] + nums[j] + nums[k] == 0.
The string PAYPALISHIRING is written in a zigzag pattern on a given number of rows like read line by line: “PAHNAPLSIIGYIR”.
Given two sorted arrays nums1 and nums2 of size m and n respectively, return the median of the two sorted arrays. The overall run time complexity should be O(log (m+n)).
Given a string s, find the length of the longest substring without repeating characters.
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 numbers and return the sum as a linked list.
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, and you may not use the same element twice.
Given an integer array nums sorted in non-decreasing order, remove the duplicates in-place such that each unique element appears only once. The relative order of the elements should be kept the same.
You are given an integer array prices where prices[i] is the price of a given stock on the ith day. On each day, you may decide to buy and/or sell the stock. You can only hold at most one share of the stock at any time. However, you can buy it then immediately sell it on the same day. Find and return the maximum profit you can achieve.