POJ 3461 KMP

链接：

http://poj.org/problem?id=3461

代码：

char a[MAXN], b[MAXN];
int Next[MAXN];
int sum;

void buildNext(char P[]) {
    int m = strlen(P);
    int i = 0, j;
    j = Next[0] = -1;
    while (i < m) {
        while (-1 != j && P[i] != P[j]) j = Next[j];
        Next[++i] = ++j;
    }
}

void kmp(char P[], char T[]) {
    int n = strlen(T), i = 0;
    int m = strlen(P), j = 0;
    buildNext(P);
    while (i < n) {
        while (-1 != j && T[i] != P[j]) j = Next[j];
        i++, j++;
        if (j >= m) sum++, j = Next[j];
    }
}

int main() {
    int T;
    cin >> T;
    while (T--) {
        sum = 0;
        memset(Next, 0, sizeof(Next));
        scanf("%s%s", a, b);
        kmp(a, b);
        cout << sum << endl;
    }
    return 0;
}