原题地址:https://oj.leetcode.com/problems/triangle/ 题意: 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 following triangle [ [], [,4], [6,,7], [4,,8,3] ]…

导航页-LeetCode专题-Python实现 相关代码已经上传到github:https://github.com/exploitht/leetcode-python 文中代码为了不动官网提供的初始几行代码内容,有一些不规范的地方,比如函数名大小写问题等等:更合理的代码实现参考我的github repo 1.读题 Implement strStr(). Returns the index of the first occurrence of needle in haystack, or -1…

导航页-LeetCode专题-Python实现 相关代码已经上传到github:https://github.com/exploitht/leetcode-python 文中代码为了不动官网提供的初始几行代码内容,有一些不规范的地方,比如函数名大小写问题等等:更合理的代码实现参考我的github repo 1.读题 Given an array and a value, remove all instances of that value in place and return the new…

导航页-LeetCode专题-Python实现 相关代码已经上传到github:https://github.com/exploitht/leetcode-python 文中代码为了不动官网提供的初始几行代码内容,有一些不规范的地方,比如函数名大小写问题等等:更合理的代码实现参考我的github repo 1.读题 Given a sorted array, remove the duplicates in place such that each element appear only onc…

导航页-LeetCode专题-Python实现 相关代码已经上传到github:https://github.com/exploitht/leetcode-python 文中代码为了不动官网提供的初始几行代码内容,有一些不规范的地方,比如函数名大小写问题等等:更合理的代码实现参考我的github repo 1.读题 Merge two sorted linked lists and return it as a new list. The new list should be made by s…

导航页-LeetCode专题-Python实现 相关代码已经上传到github:https://github.com/exploitht/leetcode-python 文中代码为了不动官网提供的初始几行代码内容,有一些不规范的地方,比如函数名大小写问题等等:更合理的代码实现参考我的github repo 1.读题 Given a string containing just the characters '(', ')', '{', '}', '[' and ']', determine if…

导航页-LeetCode专题-Python实现 相关代码已经上传到github:https://github.com/exploitht/leetcode-python 文中代码为了不动官网提供的初始几行代码内容,有一些不规范的地方,比如函数名大小写问题等等:更合理的代码实现参考我的github repo 1.读题 Determine whether an integer is a palindrome. Do this without extra space. 这一题描述很简单,判断一个数字是…

导航页-LeetCode专题-Python实现 相关代码已经上传到github:https://github.com/exploitht/leetcode-python 文中代码为了不动官网提供的初始几行代码内容,有一些不规范的地方,比如函数名大小写问题等等:更合理的代码实现参考我的github repo 1.读题 Write a function to find the longest common prefix string amongst an array of strings. 很简单的…

导航页-LeetCode专题-Python实现 相关代码已经上传到github:https://github.com/exploitht/leetcode-python 文中代码为了不动官网提供的初始几行代码内容,有一些不规范的地方,比如函数名大小写问题等等:更合理的代码实现参考我的github repo 1.读题 Given a roman numeral, convert it to an integer. Input is guaranteed to be within the range…

导航页-LeetCode专题-Python实现 相关代码已经上传到github:https://github.com/exploitht/leetcode-python 文中代码为了不动官网提供的初始几行代码内容,有一些不规范的地方,比如函数名大小写问题等等:更合理的代码实现参考我的github repo 1.读题 Reverse digits of an integer. Example1: x = 123, return 321 Example2: x = -123, return -321…

导航页-LeetCode专题-Python实现 相关代码已经上传到github:https://github.com/exploitht/leetcode-python 文中代码为了不动官网提供的初始几行代码内容,有一些不规范的地方,比如函数名大小写问题等等:更合理的代码实现参考我的github repo 1.读题 Given an array of integers, return indices of the two numbers such that they add up to a sp…

LeetCode专题-Python实现之第1题:Two Sum LeetCode专题-Python实现之第7题:Reverse Integer LeetCode专题-Python实现之第9题:Palindrome Number LeetCode专题-Python实现之第13题:Roman to Integer LeetCode专题-Python实现之第14题:Longest Common Prefix LeetCode专题-Python实现之第20题:Valid Parentheses Leet…

原题地址:https://oj.leetcode.com/problems/pascals-triangle/ 题意: Given numRows, generate the first numRows of Pascal's triangle. For example, given numRows = 5,Return [ [1], [1,1], [1,2,1], [1,3,3,1], [1,4,6,4,1] ] 解题思路:杨辉三角的求解. 代码: class Solution: # @ret…

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 following triangle [ [], [,4], [6,,7], [4,,8,3] ] The minimum path sum from top to bottom is 11 (i.e.,…

/** * Source : https://oj.leetcode.com/problems/triangle/ * * * 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 following triangle * * [ * [2],…

原题地址:https://oj.leetcode.com/problems/anagrams/ 题意: Given an array of strings, return all groups of strings that are anagrams. Note: All inputs will be in lower-case. 解题思路:anagram的意思是:abc,bac,acb就是anagram.即同一段字符串的字母的不同排序.将这些都找出来.这里使用了哈希表,即Python中的dic…

原题地址:https://oj.leetcode.com/problems/permutations/ 题意: Given a collection of numbers, return all possible permutations. For example,[1,2,3] have the following permutations:[1,2,3], [1,3,2], [2,1,3], [2,3,1], [3,1,2], and [3,2,1]. 解题思路:穷举一个集合的全排列.这个就…

118. Pascal's Triangle Given numRows, generate the first numRows of Pascal's triangle. For example, given numRows = 5,Return [ [1], [1,1], [1,2,1], [1,3,3,1], [1,4,6,4,1] ] class Solution(object): def generate(self, numRows): """ :type numR…

1. Two Sum 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 you may not use the same element twice. Example: Given nums = [2,…

题目: 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 following triangle [ [], [,4], [6,,7], [4,,8,3] ] The minimum path sum from top to bottom is 11 (i…

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 following triangle [ [], [,4], [6,,7], [4,,8,3] ] The minimum path sum from top to bottom is 11 (i.e.,…

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 following triangle [ [], [,4], [6,,7], [4,,8,3] ] The minimum path sum from top to bottom is 11 (i.e.,…

题意:给一个用序列堆成的三角形,第n层的元素个数为n,从顶往下,每个元素可以选择与自己最近的两个下层元素往下走,类似一棵二叉树,求最短路. [], [,4], [6,,7], [4,,8,3] 注意:这里可以2->3>5>1,也可以2->4>5->1,隔层相邻就可以走. 思路:可以从下往上走,也可以从上往下走.都是O(n)的空间,平方阶的复杂度. 从下往上可能更简洁,因为比较到最后只有一个元素,就是为答案了,速度自然也就快,每遍历一层就有1个被淘汰. 然而我一开始想到的…

1.题目描述 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 following triangle   [ [2], [3,4], [6,5,7], [4,1,8,3] ] The minimum path sum from top to bott…

博客域名:http://www.xnerv.wang 原标题页:https://oj.leetcode.com/problems/rotate-image/ 题目类型:下标计算 难度评价:★★★ 本文地址:http://blog.csdn.net/nerv3x3/article/details/37968757 You are given an n x n 2D matrix representing an image. Rotate the image by 90 degrees (clock…

原题地址:https://oj.leetcode.com/problems/candy/ 题意: There are N children standing in a line. Each child is assigned a rating value. You are giving candies to these children subjected to the following requirements: Each child must have at least one candy…

原题地址:https://oj.leetcode.com/problems/subsets/ 题意:枚举所有子集. 解题思路:碰到这种问题,一律dfs. 代码: class Solution: # @param S, a list of integer # @return a list of lists of integer def subsets(self, S): def dfs(depth, start, valuelist): res.append(valuelist) if depth…

原题地址:https://oj.leetcode.com/problems/combinations/ 题意:组合求解问题. 解题思路:这种求组合的问题,需要使用dfs来解决. 代码: class Solution: # @return a list of lists of integers def combine(self, n, k): def dfs(start, valuelist): if self.count == k: ret.append(valuelist); return f…

原题地址:https://oj.leetcode.com/problems/n-queens/ 题意:经典的N皇后问题. 解题思路:这类型问题统称为递归回溯问题,也可以叫做对决策树的深度优先搜索(dfs).N皇后问题有个技巧的关键在于棋盘的表示方法,这里使用一个数组就可以表达了.比如board=[1, 3, 0, 2],这是4皇后问题的一个解,意思是:在第0行,皇后放在第1列:在第1行,皇后放在第3列:在第2行,皇后放在第0列:在第3行,皇后放在第2列.这道题提供一个递归解法,下道题使用非递归.…

Triangle 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 following triangle[     [2],    [3,4],   [6,5,7],  [4,1,8,3]]The minimum path sum from top to…