KMP字符串匹配 (储备)

#include<iostream>
#include<cstdio>
#include<cstdlib>
#include<cstring>
#include<algorithm>
using namespace std;

int ne[1005];
char s[1001], f[1001];
int xlen, ylen;

void getnext(char *a)
{
    int len = strlen(a);
    int i = 0, j = -1;
    ne[0] = -1;
    while(i < len)
    {
        if(j == -1 || a[i] == a[j])
        {
            i++;
            j++;
            ne[i] = j;
        }
        else j = ne[j];
    }
}

int KMPsearch(char *x, char *y)
{
    getnext(y);
    int i = 0, j = 0;
    while(i < xlen && j < ylen)
    {
        if(j == -1 || x[i] == y[j])
        {
            i++;
            j++;
        }
        else j = ne[j];
    }
    if(j == ylen) return i - j + 1;
    else return -1;
}

int main()
{
    scanf("%s %s", &s, &f);
    xlen = strlen(s);
    ylen = strlen(f);
    //getnext(f);
    cout << KMPsearch(s, f) << endl;    
    /*for(int i = 0; i < strlen(f); i++) printf("%d ", ne[i]); printf("\n");*/
    return 0;
}
    原文作者:KMP算法
    原文地址: https://blog.csdn.net/Izayoi_w/article/details/79110776
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