Валетный код

#include <bits/stdc++.h>

#define pb push_back
#define F first
#define S second
#define ll long long

using namespace std;

int dp[512][123456];

int main() {
    ios_base::sync_with_stdio(0);
    cin.tie(0);
    cout.tie(0);
#ifdef LOCAL
    freopen("input.txt","r",stdin);
    freopen("output.txt","w",stdout);
#endif
    int n,m;
    cin>>n>>m;
    vector <int> a(n);
    ll sum = 0;
    for ( int i = 0; i < n; i++ ) {
        cin>>a[i];
        sum += a[i];
    }
    if ( sum % m == 0 ) {
        cout<<n;
        return 0;
    }
    for ( int i = 0; i < n; i++ )
        dp[i][a[i]%m] = 1;
    for ( int i = 1; i < n; i++ ) {
        for ( int j = 0; j < m; j++ ) {
            if ( dp[i-1][j] != 0 ) dp[i][j] = max( dp[i][j], dp[i-1][j] + 0 );
             if ( dp[i-1][(j-a[i]+m)%m] != 0 ) dp[i][j] = max( dp[i][j], dp[i-1][(j-a[i]+m)%m] + 1 );
        }
    }
    for ( int i = 0; i < n; i++ ) {
        for ( int j = 0; j < m; j++ )
            cout<<dp[i][j]<<' ';
        cout<<endl;
    }
    cout<<dp[n-1][0];
    return 0;
}