Submission #869320

#	Time	Username	Problem	Language	Result	Execution time	Memory
869320		prohacker	Split the sequence (APIO14_sequence)	C++14	39 / 100	115 ms	5464 KiB

sequence

#include <bits/stdc++.h>
#define ll long long
#define ld long double

using namespace std;

const int N = 1010;
const int INF = INT_MAX;
const int mod = 1e9+7;

int n,m;
ll dp[N][210],ans;
int s[N],trace[N][210];
stack<int> st;

int get(int l, int r) {
    return s[r] - s[l-1];
}

signed main()
{
    if (fopen("task.inp", "r")) {
        freopen("task.inp", "r", stdin);
        freopen("task.out", "w", stdout);
    }
    ios_base::sync_with_stdio(0);
    cin.tie(0);
    cout.tie(0);
    cin >> n >> m;
    for(int i = 1 ; i <= n ; i++) {
        int x; cin >> x;
        s[i] = s[i-1] + x;
    }
//    s[n+1] = s[n];
    for(int k = 1 ; k <= m ; k++) {
        for(int i = k ; i <= n ; i++) {
            for(int j = i-1 ; j >= 0 ; j--) {
                if(dp[j][k-1]+1LL*(s[i]-s[j])*(s[n]-s[i]) > dp[i][k]) {
                    dp[i][k] = dp[j][k-1]+1LL*(s[i]-s[j])*(s[n]-s[i]);
                    trace[i][k] = j;
                }
            }
        }
    }
    int id;
    ans = 0;
    for(int i = 1 ; i <= n ; i++) {
        if(dp[i][m] > ans) {
            ans = dp[i][m];
            id = i;
        }
    }
    cout << ans << '\n';
    while(m > 0) {
        cout << id << " ";
        id = trace[id][m];
//        st.push(n);
        m--;
    }
//    while(!st.empty()) {
//        cout << st.top() << " ";
//        st.pop();
//    }
    return 0;
}

Compilation message (stderr)

sequence.cpp: In function 'int main()':
sequence.cpp:23:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   23 |         freopen("task.inp", "r", stdin);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~
sequence.cpp:24:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   24 |         freopen("task.out", "w", stdout);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~
sequence.cpp:56:12: warning: 'id' may be used uninitialized in this function [-Wmaybe-uninitialized]
   56 |         id = trace[id][m];
      |         ~~~^~~~~~~~~~~~~~

• Subtask 1: 0 / 11
• Subtask 2: 11 / 11
• Subtask 3: 11 / 11
• Subtask 4: 17 / 17
• Subtask 5: 0 / 21
• Subtask 6: 0 / 29