831.KMP字符串（AcWing）

KMP模板題

#include <iostream>
#include <cstdio>
#include <fstream>
#include <algorithm>
#include <cmath>
#include <deque>
#include <vector>
#include <queue>
#include <string>
#include <cstring>
#include <map>
#include <stack>
#include <set>
#include<algorithm>
#include<stdio.h>
#define N 10000+5
#define inf 0x3f3f3f3f
using namespace std;
typedef long long ll;
int n, m;
int nex[1000005];
char s1[1000005], s2[1000005];
void getnex()
{
	//int len2 = strlen(s2);

	nex[0] = { -1 };
	int k = -1;
	int j = 0;
	while (j < m)
	{
		if (k == -1 || s2[j] == s2[k])
		{
			++k;
			++j;
			nex[j] = k;
		}
		else
		{
			k = nex[k];
		}
	}
}
void kmp()
{
	int i = 0, j = 0;
	//int len1 = strlen(s1);
	//int len2 = strlen(s2);

	int ans = 0;
	while (i < n)
	{

		if (j == -1 || s1[i] == s2[j])
		{

			i++;
			j++;
			if (j == m)//找到模式串
			{
				printf("%d ",i - m);//返回第一次出現的位置

			}

		}
		else
		{
			j = nex[j];
		}
	}
	//return -1;
}
int main()
{
	int T;

		memset(nex, -1, sizeof(nex));
		scanf("%d",&m);

			scanf("%s", s2);
        scanf("%d",&n);

			scanf("%s", s1);
		getnex();
		 kmp();


	return 0;
}