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/description/ 题目大意:字符串匹配,从字符串中,找到给定字符串第一次出现的位置下标,并返回. 法一:暴力,两个for循环,逐一比较每一个可能的字符串,一旦找到,则返回.代码如下(耗时508ms->10ms): public int strStr(String haystack, String needle) { int res = -1, len_h = haystack.leng…

# -*- 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…

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.…

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()…

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…

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. 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…

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-…

Implement strStr() Implement strStr(). Returns a pointer to the first occurrence of needle in haystack, or null if needle is not part of haystack. 解法一:暴力解 class Solution { public: int strStr(string haystack, string needle) { int m = haystack.size();…