题解 | 模意义下最大子序列和（Easy Version）

#include <bits/stdc++.h>
#define fi first
#define se second
using namespace std;
using LL = long long;
constexpr int N = 2e5 + 5;
int n, m;
int a[20];

void solve() {
    cin >> n >> m;
    for (int i = 0; i < n; ++i)cin >> a[i];
    int res = 0;
    for (int i = 1, s; i < 1 << n; ++i) {
        s = 0;
        for (int j = 0; j < n; ++j)
            if (i >> j & 1)s = (s + a[j]) % m;
        res = max(res, s);
    }
    cout << res << "\n";
}

int main() {
    ios::sync_with_stdio(false);
    cin.tie(nullptr);
    cout << fixed << setprecision(15);
    int tt = 1;
    // cin >> tt;
    while (tt--) solve();
}