小刀初试

摘要： Determine if a Sudoku is valid, according to: Sudoku Puzzles - The Rules.The Sudoku board could be partially filled, where empty cells are filled with... 阅读全文

摘要： Given a string containing just the characters '(', ')', '{', '}', '[' and ']', determine if the input string is valid.The brackets must close in the c... 阅读全文

摘要： Follow up for "Unique Paths":Now consider if some obstacles are added to the grids. How many unique paths would there be?An obstacle and empty space i... 阅读全文

摘要： Ranking: **A 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 righ... 阅读全文

摘要： Given a triangle, find the minimum path sum from top to bottom. Each step you may move to adjacent numbers on the row below.For example, given the fol... 阅读全文

摘要： Given n non-negative integers representing an elevation map where the width of each bar is 1, compute how much water it is able to trap after raining.... 阅读全文

摘要： Given an array of words and a length L, format the text such that each line has exactly L characters and is fully (left and right) justified.You shoul... 阅读全文

摘要： Given a binary tree, check whether it is a mirror of itself (ie, symmetric around its center).For example, this binary tree is symmetric: 1 / \ ... 阅读全文

摘要： Given a linked list, swap every two adjacent nodes and return its head.For example,Given 1->2->3->4, you should return the list as 2->1->4->3.Your alg... 阅读全文

摘要： You are given a string, S, and a list of words, L, that are all of the same length. Find all starting indices of substring(s) in S that is a concatena... 阅读全文