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one day an cannon!!! or one week five cannons!!! 500 keyboard row 题目说明： Given a List of words, return the words that can be typed using letters of alphabet on only one row'

leetcode 530. Minimum Absolute Difference in BST #coding=utf-8 ''' Given a binary search tree with non-negative values, find the minimum absolute difference between values of any two nod

leetcode 506. Relative Ranks #coding=utf-8 '''Given scores of N athletes, find their relative ranks and the people with the top three highest scores, who will be awarded medals: "Gold Medal",

python leetcode  求两个数组的交集350. Intersection of Two Arrays II Given two arrays, write a function to compute their intersection. Example: Given nums1 = [1, 2, 2, 1], nums2 = [2, 2],

Python leetcode leetcode  383. Ransom Note Given an arbitrary ransom note string and another string containing letters from all the magazines, write a function that will return true if the ran

Python leetcode 453. Minimum Moves to Equal Array Elements Given a non-empty integer array of size n, find the minimum number of moves required to make all array elements equal, where a

Python leetcode 404. Sum of Left Leaves Find the sum of all left leaves in a given binary tree. Example:     3    / \   9  20     /  \    15   7 There are two left leaves in

Python leetcode 387. First Unique Character in a String Given a string, find the first non-repeating character in it and return it's index. If it doesn't exist, return -1. Examples:

python leetcode  122. Best Time to Buy and Sell Stock II Say you have an array for which the ith element is the price of a given stock on day i. Design an algorithm to find the maximu

Python leetcode 242. Valid Anagram 242. Valid Anagram Given two strings s and t, write a function to determine if t is an anagram of s. For example, s = "anagram", t = "nagaram"

python leetcode 504. Base 7 Given an integer, return its base 7 string representation. 将十进制转为7进制，其他进制的转换类似。 记住几个常见的内置函数。bin(),hex(),oct()....分别是十进制数转二进制，十六机制，和八进制。 Example 1:

409. Longest Palindrome 求给定一个字符串的最长回文字符串的长度。 Given a string which consists of lowercase or uppercase letters, find the length of the longest palindromes that can be built with th

Python   leetcode 447. Number of Boomerangs 给定n个二维坐标点，存在这样的坐标点三元组（i,j,k），就是i到j的距离等于i到k的距离，其中i,j,k都是坐标点。同时，i到k的距离等于i到j的距离，那么就有两种形式[i,j,k]和[i,k,j]，都表示这样特点的三元组。那么根据题意，这就是boomerang。每个符合的三个

Given an array of 2n integers, your task is to group these integers into n pairs of integer, say (a1, b1), (a2, b2), ..., (an, bn) which makes sum of min(ai, bi) for all i from 1 to n as large a

226. Invert Binary Tree Invert a binary tree. 4 / \ 2 7 / \ / \ 1 3 6 9 to      4    /   \   7     2  / \   / \ 9   6 3   1 #coding=utf-8

371. Sum of Two Integers Calculate the sum of two integers a and b, but you are not allowed to use the operator + and -. Example: Given a = 1 and b = 2, return 3. 首先水一波，自己写的牛头不对马嘴，

one day one cannon or  one week five connon #coding=utf-8 ''' Given a positive integer, output its complement number. The complement strategy is to flip the bits of its binary representatio

one day one cannon or  one week five cannons 496 Next Greater Element I You are given two arrays (without duplicates) nums1 and nums2 where nums1’s elements are subset of nums2. Find all

one day one cannon or  one week five cannons 412. Fizz Buzz Write a program that outputs the string representation of numbers from 1 to n. But for multiples of three it should output

one day a cannon or one week five cannons leetcode 461 hamming distance  (Source) The Hamming distance between two integers is the number of positions at which the corresponding bits are diffe

简单来说就是求给定一个数的每个位置数值的相加 #coding=utf-8 ''' Given a non-negative integer num, repeatedly add all its digits until the result has only one digit. For example: Given num = 38, the process

#coding=utf-8 ''' Given an array nums, write a function to move all 0's to the end of it while maintaining the relative order of the non-zero elements. For example, given nums = [0, 1, 0, 3, 12], aft

很难坚持啊，一题要好长时间....... 不搞什么虚的了，还是尽量坚持下去..... You are given a map in form of a two-dimensional integer grid where 1 represents land and 0 represents water. Grid cells are connected horizontal

485. Max Consecutive Ones Given a binary array, find the maximum number of consecutive 1s in this array. 就是让你求一个二进制数组中字符1的最大长度..... Example 1: Input: [1,1,0,1,1,1] Output: 3 Explanation:

Given an array of integers, every element appears twice except for one. Find that single one. Note: Your algorithm should have a linear runtime complexity. Could you implement it without using e

448. Find All Numbers Disappeared in an Array Given an array of integers where 1 ≤ a[i] ≤ n (n = size of array), some elements appear twice and others appear once. Find all the elements of

#coding=utf-8 ''' Given a word, you need to judge whether the usage of capitals in it is right or not. We define the usage of capitals in a word to be right when one of the following cases hold

leetcode  104. Maximum Depth of Binary Tree #coding=utf-8 ''' Given a binary tree, find its maximum depth. The maximum depth is the number of nodes along the longest path from the root

389. Find the Difference Given two strings s and t which consist of only lowercase letters. String t is generated by random shuffling string s and then add one more letter at a random positi

A matrix is Toeplitz if every diagonal from top-left to bottom-right has the same element. Now given an M x N matrix, return True if and only if the matrix is Toeplitz.   Example 1: Input: m