KMP算法模板

#include<iostream>
#include<cstdio>
#include<cmath>
#include<algorithm>
#include<cstring>
#include<vector>
using namespace std;
int N, fail[2000000], ANS[2000000];
char pat[2000000], text[2000000];
inline void KMP() {
    int n = strlen(pat);
    for (int i = 0; i <= n + 1; i++) fail[i] = 0;
    for (int i = 1; i <= n - 1; i++) {
        int j = i;
        while (j>0) {
            j = fail[j];
            if (pat[j] == pat[i]) {
                fail[i + 1] = j + 1;
                break;
            }
        }
    }
    ANS[0] = 0;
    int m = strlen(text);
    for (int i = 0, j = 0; i <= m - 1; i++) {
        if (j <= n - 1 && text[i] == pat[j]) j++;
        else {
            while (j > 0) {
                j = fail[j];
                if (text[i] == pat[j]) {
                    j++; break;
                }
            }
        }
        if (j == n) ANS[++ANS[0]] = i - n + 1;
    }
}
int main() {
    scanf("%d", &N);
    while (N--) {
        cin >> pat >> text;
        KMP();
        printf("%d
", ANS[0]);
    }
    return 0;
}