这个题目是典型的KMP算法,当然也可以试试BM,当然有关KMP和BM的介绍阮一峰曾经写过比较好的科普,然后july也有讲解,不过那个太长了. 先放题目吧: 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 func…

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",…

1 题目: 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…

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…

Implement strStr(). Returns the index of the first occurrence of needle in haystack, or -1 if needle is not part of haystack. 思路: 注意,在for循环中条件有计算得到的负数时, 一定要把计算括起来转换为int, 否则会默认转换为uchar 负数就会被误认为是一个很大的数字. ; i < - ); ++i) 实现很常规: int strStr(string haystac…

Implement strStr() Implement strStr(). Returns the index of the first occurrence of needle in haystack, or -1 if needle is not part of haystack. 最简单的思路,逐一比较: class Solution { public: int strStr(char *haystack, char *needle) { int n1=strlen(haystack);…

Implement strStr(). Returns the index of the first occurrence of needle in haystack, or -1 if needle is not part of haystack. 解题思路一: 暴力枚举,JAVA实现如下: static public int strStr(String haystack, String needle) { for(int i=0;i<=haystack.length()-needle.len…

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(). 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…

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: Implement strStr(). Returns the index of the first occurrence of needle in haystack, or -1 if needle is not part of haystack. 思路: 题意:判断一个字符串是否包含另外一个 写一个函数判断一个字符串从坐标k,是否相等于另一个,遍历一下,i < a.length() -b.length()+1,b.length() < a.length() - 代码: public…

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…

题目要求:Implement strStr() Implement strStr(). Returns the index of the first occurrence of needle in haystack, or -1 if needle is not part of haystack. Java: public int strStr(String haystack, String needle) { if (haystack == null || needle == null) {…

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;…

这道题是LeetCode里的第28道题. 题目描述: 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 = &q…

class Solution { public: int strStr(char *haystack, char *needle) { , skip[]; char *str = haystack, *substr = needle; int len_src = strlen(str), len_sub = strlen(substr); // preprocess ; i < ; i++) skip[i] = len_sub; ; ; i < last;i++) skip[substr[i]…

字符串的匹配,返回匹配开始的位置,直接用暴力方式求解.为了更快的匹配,定义一个指针表示待匹配的字符串的长度,当长度不足时,可 直接停止匹配. char *strStr(char *haystack, char*needle) { char* p1; char* p2; char* p1_advance=haystack; //当字符串数量不足时,直接停止匹配 ]; *p2; p2++) p1_advance++; for (p1 = haystack; *p1_advance; p1_advan…

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…

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…

Github leetcode 我的解题仓库   https://github.com/interviewcoder/leetcode 题目: 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 ha…

# -*- 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…

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-…

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…

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…

LeetCode解题之Implement strStr() 原题 实现字符串子串匹配函数strStr(). 假设字符串A是字符串B的子串.则返回A在B中首次出现的地址.否则返回-1. 注意点: - 空字符串是全部字符串的子串,返回0 样例: 输入: haystack = "abc", needle = "bc" 输出: 1 输入: haystack = "abc", needle = "gd" 输出: -1 解题思路 字符串匹…

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…

Implement strStr(). Returns the index of the first occurrence of needle in haystack, or -1 if needle is not part of haystack. 注:直接看题目可能会有些偏差,因为容易认为 needle是一个字符,那就也太容易了,实则,haystack和needle都是字符串(注意是字符串不是数组) 解法思路: 暴力搜索: public class Solution { public int…

Implement strStr(). Returns a pointer to the first occurrence of needle in haystack, or null if needle is not part of haystack. I wrote that function before in practice without knowing anything about strStr(), so I have a pretty clear brute-force sol…