递推函数

#include <bits/stdc++.h>
using namespace std;
int main() {
    int k, m;
    cin >> k >> m;
    vector<int> f(10 + 1, 0);
    for (int i = 1; i < 10; ++i) f[i] = i;
    vector<int> a(10 + 1);
    for (int i = 1; i <= 10; ++i) cin >> a[i];
    for (int i = 10; i <= k; ++i) {
        /* 每一轮计算的结果存放在f[10] */
        for (int j = 1; j <= 10; j++) {
            f[10] += f[10 - j] * a[j];
            f[10] %= m;
        }
        /* 数组整体向左滚动一位 */
        for (int j = 0; j < 10; ++j) f[j] = f[j + 1];
        /* 清空f[10] */
        f[10] = 0;
    }
    cout << f[9] << endl;
    return 0;
}