28. Implement strStr() Implement strStr(). Returns the index of the first occurrence of needle in haystack, or -1 if needle is not part of haystack. 思路:子串匹配,朴素匹配.…

Implement strStr(). Return the index of the first occurrence of needle in haystack, or -1 if needle is not part of haystack. Example 1: Input: haystack = "hello", needle = "ll" Output: 2 Example 2: Input: haystack = "aaaaa",…

题目链接: https://leetcode.com/problems/implement-strstr/?tab=Description   Problem : 实现找子串的操作:如果没有找到则返回-1  ,如果找到则返回第一个匹配位置第一个字符的下标   遍历操作,依次遍历子串中的元素,从长串的第i个元素位置开始,当成功遍历结束子串所有元素时,返回此时的i即时所求结果, 如果此时的i+j已经等于长串的个数,那么表示没有找到,返回-1    参考代码: package leetcode_50;…

Implement strStr(). Returns the index of the first occurrence of needle in haystack, or -1 if needle is not part of haystack. 问题:实现 strStr() 函数.即在  haystack 中匹配 needle 字符串. 可以理解为,实际上这道题是在问如何实现 KMP(Knuth–Morris–Pratt) 算法.这是个效率比较高的算法,只需要扫一遍 haystack 就可…

Brute Force算法,时间复杂度 O(mn) def strStr(haystack, needle): m = len(haystack) n = len(needle) if n == 0: return 0 if m < n: return -1 for i in range(m - n - 1): for j in range(n): if haystack[i + j] != needle[j]: break elif j == n - 1: return i return -1…

题目描述: Implement strStr(). Returns the index of the first occurrence of needle in haystack, or -1 if needle is not part of haystack. Update (2014-11-02): The signature of the function had been updated to return the index instead of the pointer. If you…

Implement strStr(). Return the index of the first occurrence of needle in haystack, or -1 if needle is not part of haystack. Example 1: Input: haystack = "hello", needle = "ll" Output: 2 Example 2: Input: haystack = "aaaaa",…

Implement strStr(). Return the index of the first occurrence of needle in haystack, or -1 if needle is not part of haystack. Example 1: Input: haystack = "hello", needle = "ll" Output: 2 Example 2: Input: haystack = "aaaaa",…

Implement strStr(). Returns the index of the first occurrence of needle in haystack, or -1 if needle is not part of haystack. 解法: 这道题让我们在一个字符串中找另一个字符串第一次出现的位置,那我们首先要做一些判断,如果子字符串为空,则返回0,如果子字符串长度大于母字符串长度,则返回-1.然后我们开始遍历母字符串,我们并不需要遍历整个母字符串,而是遍历到剩下的长度和子字符…

题目: class Solution { public: int strStr(string haystack, string needle) { if(needle.empty()){ return 0; } vector<int> next; int i = 0; int j = 0; int sLen = haystack.size(); int tLen = needle.size(); next = getNext(needle); while((i<sLen)&&am…

# -*- coding: utf8 -*-'''__author__ = 'dabay.wang@gmail.com' 28: Implement strStr()https://oj.leetcode.com/problems/implement-strstr/ Implement strStr().Returns the index of the first occurrence of needle in haystack, or -1 if needle is not part of h…

1.题目 28. Implement strStr()——Easy Implement strStr(). Return the index of the first occurrence of needle in haystack, or -1 if needle is not part of haystack. Example 1: Input: haystack = "hello", needle = "ll" Output: 2 Example 2: Inp…

28. 实现 strStr() 实现 strStr() 函数. 给定一个 haystack 字符串和一个 needle 字符串,在 haystack 字符串中找出 needle 字符串出现的第一个位置 (从0开始).如果不存在,则返回 -1. 示例 1: 输入: haystack = "hello", needle = "ll" 输出: 2 示例 2: 输入: haystack = "aaaaa", needle = "bba"…

Implement strstr() 实现strstr函数功能 whowhoha@outlook.com Question: Implement strstr(). Returns the index of the first occurrence of needle in haystack, or –1 if needle is not part of haystack. int strStr(string haystack, string needle) { for (int i = 0;…

Implement strStr(). Returns the index of the first occurrence of needle in haystack, or -1 if needle is not part of haystack public class Solution { public int strStr(String haystack, String needle) { if(haystack==null||needle==null) return -1; int l…

28. Implement strStr()[easy] Implement strStr(). Returns the index of the first occurrence of needle in haystack, or -1 if needle is not part of haystack. 解法一: class Solution { public: int strStr(string haystack, string needle) { if (haystack.empty()…

# 前端与算法 leetcode 28.实现 strStr() 题目描述 28.移除元素 概要 这道题的意义是实现一个api,不是调api,尽管很多时候api的速度比我们写的快(今天这个我们可以做到和indexOf一样快),但我们还是要去了解api内实现的原理,在我们所熟悉的v8引擎中,indexOf使用了kmp和bm两种算法,在主串长度小于7时使用kmp,大于7的时候使用bm,bf咱就不说了哈,那个其实就是爆破算法, 提示 数据结构,kmp,bm 解析 kmp算法的核心其实就是动态规划,明确了…

[JavaScript]Leetcode每日一题-实现strStr() [题目描述] 实现 strStr() 函数. 给你两个字符串 haystack 和 needle ,请你在 haystack 字符串中找出 needle 字符串出现的第一个位置(下标从 0 开始).如果不存在,则返回 -1 . 说明: 当 needle 是空字符串时,我们应当返回什么值呢?这是一个在面试中很好的问题. 对于本题而言,当 needle 是空字符串时我们应当返回 0 .这与 C 语言的 strstr() 以及 J…

Implement a magic directory with buildDict, and search methods. For the method buildDict, you'll be given a list of non-repetitive words to build a dictionary. For the method search, you'll be given a word, and judge whether if you modify exactly one…

翻译 用队列来实现栈的例如以下操作. push(x) -- 将元素x加入进栈 pop() -- 从栈顶移除元素 top() -- 返回栈顶元素 empty() -- 返回栈是否为空 注意: 你必须使用一个仅仅有标准操作的队列. 也就是说,仅仅有push/pop/size/empty等操作是有效的. 队列可能不被原生支持.这取决于你所用的语言. 仅仅要你仅仅是用queue的标准操作,你能够用list或者deque(double-ended queue)来模拟队列. 你能够如果全部的操作都是有效的(…

Implement the following operations of a stack using queues. push(x) -- Push element x onto stack. pop() -- Removes the element on top of the stack. top() -- Get the top element. empty() -- Return whether the stack is empty. Notes: You may assume that…

Implement the following operations of a queue using stacks. push(x) -- Push element x to the back of queue. pop() -- Removes the element from in front of queue. peek() -- Get the front element. empty() -- Return whether the queue is empty. Notes: You…

字典树(查找树) 26个分支作用:检测字符串是否在这个字典里面插入.查找 字典树与哈希表的对比:时间复杂度:以字符来看:O(N).O(N) 以字符串来看:O(1).O(1)空间复杂度:字典树远远小于哈希表 前缀相关的题目字典树优于哈希表字典树可以查询abc是否有ab的前缀 字典树常考点:1.字典树实现2.利用字典树前缀特性解题3.矩阵类字符串一个一个字符深度遍历的问题(DFS+trie) dfs树和trie树同时遍历 word searchIIdfs+hash:时间复杂度大,后面遍历到有些字符就…

Implement strStr(). Returns the index of the first occurrence of needle in haystack, or -1 if needle is not part of haystack. Update (2014-11-02): The signature of the function had been updated to return the index instead of the pointer. If you still…

作者: 负雪明烛 id: fuxuemingzhu 个人博客: http://fuxuemingzhu.cn/ 目录 题目描述 题目大意 解题方法 find函数 遍历+切片 日期 题目地址:https://leetcode.com/problems/implement-strstr/description/ 题目描述 Implement strStr(). Return the index of the first occurrence of needle in haystack, or -1…

一天一道LeetCode系列 (一)题目 Implement strStr(). Returns the index of the first occurrence of needle in haystack, or -1 if needle is not part of haystack. (二)解题 第一种解法:朴素匹配算法 /* 两个指针,分别指向两个字符串的首字符 如果相等则一起向后移动,如果不同i取第一个相同字符的下一个开始继续匹配 如果最后j等于needle的长度则匹配成功,返回i-…

28.Implement strStr() Implement strStr(). Return the index of the first occurrence of needle in haystack, or -1 if needle is not part of haystack. Example 1: Input: haystack = "hello", needle = "ll" Output: 2 Example 2: Input: haystack…

https://leetcode.com/problems/implement-strstr/ 题目: Implement strStr(). Returns the index of the first occurrence of needle in haystack, or -1 if needle is not part of haystack. 思路: 判断一个string是否另一个string的子序列并返回位置. naive法:遍历查找,复杂度O(mn). advance法还有Rabi…

爱写bug(ID:icodebugs) 作者:爱写bug 实现 strStr() 函数. 给定一个 haystack 字符串和一个 needle 字符串,在 haystack 字符串中找出 needle 字符串出现的第一个位置 (从0开始).如果不存在,则返回 -1. Implement strStr(). Return the index of the first occurrence of needle in haystack, or -1 if needle is not part of…

Implement strStr(). Returns the index of the first occurrence of needle in haystack, or -1 if needle is not part of haystack. Solution:  class Solution { public: int strStr(string haystack, string needle) { //runtime:4ms int len1=haystack.size(), len…