Machine_g的博客

最近参加了一个线上笔试，记录下里面两道题 grid path 从一个田字格(2X2)的左上角出发，只允许向右或向下移动，恰好有6条路径。则对于20X15的，从左上角出发到右下角的路径共有多少条？ 思路：画图很直观。 这里先把图转换为二维矩阵，则2X2的图对应的矩阵为(3,3)，grid=[[0,0,0],[0,0,0],[0,0,0]]。由于只能向右或者向下，所以第一行以及第一列的路径都是1。即grid[0][x]=0，x in range(0,n+1)，grid[y][0]=0，y in range(0

description Given a string containing just the characters ‘(’, ‘)’, ‘{’, ‘}’, ‘[’ and ‘]’, determine if the input string is valid. An input string is valid if: Open brackets must be closed by the same...

description Roman numerals are represented by seven different symbols: I, V, X, L, C, D and M. Symbol Value I 1 V 5 X 10 L 50 C 100 D ...

leetcode T09 description Determine whether an integer is a palindrome. An integer is a palindrome when it reads the same backward as forward. Example 1: Input: 121 Output: true Example 2: Input: -121...

leetcode T07 description Given a 32-bit signed integer, reverse digits of an integer. Example 1: Input: 123 Output: 321 Example 2: Input: -123 Output: -321 Example 3: Input: 120 Output: 21 Note: As...

leetcode T01 description Given an array of integers, return indices of the two numbers such that they add up to a specific target. You may assume that each input would have exactly one solution, and y...

leetcode T14 description Write a function to find the longest common prefix string amongst an array of strings. If there is no common prefix, return an empty string “”. Example 1: Input: [“flower”,“fl...