AOJ 47 字符串匹配

KMP模板

#include <cstdio>
#include <cstring>

using namespace std;

const int maxn = 105;
int f[maxn];
char pat[maxn],str[maxn];

inline void getfail() {
    int len = strlen(pat);
    f[0] = f[1] = 0;
    for(int i = 2;i < len;i++) {
        int j = f[i - 1];
        while(j && str[i - 1] != str[j]) j = f[j];
        if(str[i - 1] == str[j]) f[i] = j + 1;
        else f[i] = 0;
    }
}

inline int kmp() {
    int lenp = strlen(pat),lens = strlen(str);
    int i = 0,j = 0;
    for(;i < lens;i++) {
        while(j && pat[j] != str[i]) j = f[j];
        if(pat[j] == str[i]) j++;
        if(j == lenp) return i - lenp + 2;
    }
    return -1;
}

int main() {
    int T; scanf("%d",&T);
    while(T--) {
        scanf("%s%s",str,pat);
        printf("%d
",kmp());
    }
    return 0;