Submission #1211545

#	Time	Username	Problem	Language	Result	Execution time	Memory
1211545		Trn115	지우개 (GA4_eraser)	C++20	100 / 100	14 ms	5704 KiB

eraser

#include <bits/stdc++.h>

#define int long long
#define fi first
#define se second
#define all(v) v.begin(), v.end()

using namespace std;

constexpr int MOD = 1e9+7;

signed main()
{
    cin.tie(0)->sync_with_stdio(0);
    if (fopen("source.inp", "r"))
    {
        freopen("source.inp", "r", stdin);
        freopen("source.out", "w", stdout);
    }

    int n; cin >> n;
    vector<int> a(n + 1);
    for (int i = 1; i <= n; ++i)
    {
        cin >> a[i];
    }

    sort(1 + all(a));
    vector<int> last(n + 1, 0);
    int cur = 0;
    for (int i = 1; i <= n; ++i)
    {
        if (a[i] != a[i - 1])
        {
            cur = i - 1;
        }
        last[i] = cur;
    }

    vector<vector<int>> dp(4, vector<int>(n + 1, 0));
    fill(all(dp[0]), 1);
    for (int i = 1; i <= 3; ++i)
    {
        for (int j = 1; j <= n; ++j)
        {
            dp[i][j] = dp[i][j - 1] + a[j] * dp[i - 1][last[j]];
            dp[i][j] %= MOD;
            //cerr << i << " " << j << " " << dp[i][j] << "\n";
        }
    }
    cout << dp[3][n];
}

Compilation message (stderr)

eraser.cpp: In function 'int main()':
eraser.cpp:17:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   17 |         freopen("source.inp", "r", stdin);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~
eraser.cpp:18:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   18 |         freopen("source.out", "w", stdout);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~

• Subtask 1: 6 / 6
• Subtask 2: 7 / 7
• Subtask 3: 16 / 16
• Subtask 4: 17 / 17
• Subtask 5: 26 / 26
• Subtask 6: 28 / 28