ZQYnn's blog

Longest Palindromic SubstringGiven a string s, find the longest palindromic substring in s. You may assume that the maximum length of s is 1000.Example 1:Input: "babad"Output: "bab"Note: "aba" i...

Longest Common SubsequenceGiven two strings text1 and text2, return the length of their longest common subsequence.A subsequence of a string is a new string generated from the original string with ...

53. Maximum SubarrayGiven an integer array nums, find the contiguous subarray (containing at least one number) which has the largest sum and return its sum.Example:Input: [-2,1,-3,4,-1,2,1,-5,4],...

House RobberYou are a professional robber planning to rob houses along a street. Each house has a certain amount of money stashed, the only constraint stopping you from robbing each of them is that a...

Dungeon Game The demons had captured the princess (P) and imprisoned her in the bottom-right corner of a dungeon. The dungeon consists of M x N rooms laid out in a 2D grid. Our valiant knight (K) w...

Minimum Path SumGiven a m x n grid filled with non-negative numbers, find a path from top left to bottom right which minimizes the sum of all numbers along its path.Note: You can only move either ...

Unique Paths IIA robot is located at the top-left corner of a m x n grid (marked ‘Start’ in the diagram below).The robot can only move either down or right at any point in time. The robot is trying...

Unique PathsA robot is located at the top-left corner of a m x n grid (marked ‘Start’ in the diagram below).The robot can only move either down or right at any point in time. The robot is trying...

Longest Increasing SubsequenceGiven an unsorted array of integers, find the length of longest increasing subsequence.Example:Input: [10,9,2,5,3,7,101,18]Output: 4 Explanation: The longest incre...

Perfect SquaresGiven a positive integer n, find the least number of perfect square numbers (for example, 1, 4, 9, 16, ...) which sum to n.Example 1:Input: n = 12Output: 3 Explanation: 12 = 4 +...

Climbing StairsYou are climbing a stair case. It takes n steps to reach to the top.Each time you can either climb 1 or 2 steps. In how many distinct ways can you climb to the top?Note: Given n will...

Fibonacci NumberThe Fibonacci numbers, commonly denoted F(n) form a sequence, called the Fibonacci sequence, such that each number is the sum of the two preceding ones, starting from 0 and 1. That ...

Pascal's TriangleGiven a non-negative integer numRows, generate the first numRows of Pascal’s triangle.In Pascal’s triangle, each number is the sum of the two numbers directly above it.Example:...