Poj 3461 KMP解法

题目大意:
给两个字符串(s1、s2),求s2中s1字符串出现的次数
解法KMP和哈希(先写KMP,哈希后面补上)
基础KMP 不做讲解 附AC代码

#include<iostream>
using namespace std;
void GetKMPNext(char *str, int *Next,int nLen)
{
	Next[0] =-1;
	int j = 0;
	int k = -1;
	while (j < nLen)
	{
		if (k == -1 || str[k] == str[j])
		{
			Next[++j] = ++k;
		}
		else
			k = Next[k];
	}
}
int main()
{
	char StrA[1000001];
	char StrB[10001];
	int Next[10001];
	int nNum = 0;
	cin >> nNum;
	
	for(int f = 0 ;f<nNum;f++)
	{
		int nMark = 0;
		cin >> StrB;
		cin >> StrA;
		int LenA = strlen(StrA);
		int LenB = strlen(StrB);
		GetKMPNext(StrB,Next, LenB);
		int j = 0;
		bool bFlag = false;
		for (int i = 0; i < LenA && j < LenB; )
		{
			if (StrA[i] == StrB[j] || j == -1)
			{
				i++;
				j++;
			}
			else
			{
				j = Next[j];
			}

			if (j == LenB)
			{
				nMark++;
				j = Next[j];
			}
		}
		printf("%d\n", nMark);
	}
	return 0;
}

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转载自blog.csdn.net/RoronoaDZoro/article/details/90748320
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