HDU1686 Oulipo

版权声明： https://blog.csdn.net/moon_sky1999/article/details/83703143

题目来源：http://acm.hdu.edu.cn/showproblem.php?pid=1686

kmp模板题。

代码：

#include <cstdio>
#include <cstdlib>
#include <cstring>
#include <cmath>
#include <algorithm>
#include <iostream>
#include <iomanip>
#include <string>
#include <vector>
#include <queue>
#include <stack>
#include <map>
#include <set>

#define ll long long
#define ull unsigned long long
#define BUG cout<<"*************************"<<endl
using namespace std;

const ll mod = 1e9;
const int maxn = 5e4 + 10;
const int maxm = 1e6 + 10000;
const double eps = 1e-8;

int nxt[maxm];
string s, t;

void get_next(int len) {
    int j = 0, k = -1;
    nxt[0] = -1;
    while (j < len) {
        if (k == -1 || t[k] == t[j]) {
            ++j;
            ++k;
            nxt[j] = k;
        } else k = nxt[k];
    }
}

int main() {
    ios::sync_with_stdio(0);
    cin.tie(0);
    cout.tie(0);
    int _;
    cin >> _;
    while (_--) {
        cin >> t >> s;
        get_next((int) t.size());
        int i = 0, j = 0, ans = 0;
        while (i < s.size()) {
            if (j == -1 || s[i] == t[j]) {
                ++i;
                ++j;
            } else j = nxt[j];
            if (j == t.size()) {
                ++ans;
                j = nxt[j];
            }
        }
        cout << ans << endl;
    }
    return 0;
}