Submission #941205

#	Time	Username	Problem	Language	Result	Execution time	Memory
941205		peterandvoi	Let's Win the Election (JOI22_ho_t3)	C++17	100 / 100	7 ms	2648 KiB

Main

#include <bits/stdc++.h>

using namespace std;

#ifdef ngu
#include "debug.h"
#else
#define debug(...) 42
#endif

const int N = 505;

int n, k;
double dp[N][N];
pair<int, int> a[N];

double get(int mid) {
    for (int i = 0; i <= n; ++i) {
        for (int j = 0; j <= k - mid; ++j) {
            dp[i][j] = 1e9;
        }
    }
    dp[0][0] = 0;
    for (int i = 1; i <= n; ++i) {
        for (int j = 0; j <= min(i, k - mid); ++j) {
            int x = i - j - 1;
            if (j > 0) {
                dp[i][j] = min(dp[i][j], dp[i - 1][j - 1] + 1.0 * a[i].first / (mid + 1));
            }
            dp[i][j] = min(dp[i][j], dp[i - 1][j] + (x < mid ? 1.0 * a[i].second / (x + 1) : 0));
        }
    }
    return dp[n][k - mid];
}

signed main() {
    ios::sync_with_stdio(false);
    cin.tie(0);
    #ifdef ngu
    freopen("test.inp", "r", stdin);
    freopen("test.out", "w", stdout);
    #endif
    cout << fixed << setprecision(15);
    cin >> n >> k;
    for (int i = 1; i <= n; ++i) {
        cin >> a[i].first >> a[i].second;
        // wtf ?
        assert(a[i].second <= 1000);
        a[i].second = a[i].second == -1 ? 1e9 : a[i].second;
    }
    sort(a + 1, a + n + 1, [&](auto x, auto y) {
        return x.second < y.second;
    });
    int l = 1, r = n, res = 0;
    for (int i = 1; i <= n; ++i) {
        r -= a[i].second == 1e9;
    }
    r = min(r, k);
    while (l <= r) {
        int mid = l + r >> 1;
        if (get(mid - 1) >= get(mid)) {
            res = mid;
            l = mid + 1;
        } else {
            r = mid - 1;
        }
    }
    cout << get(res);
}

Compilation message (stderr)

Main.cpp: In function 'int main()':
Main.cpp:60:21: warning: suggest parentheses around '+' inside '>>' [-Wparentheses]
   60 |         int mid = l + r >> 1;
      |                   ~~^~~

• Subtask 1: 5 / 5
• Subtask 2: 5 / 5
• Subtask 3: 11 / 11
• Subtask 4: 12 / 12
• Subtask 5: 33 / 33
• Subtask 6: 11 / 11
• Subtask 7: 23 / 23