Submission #1211161

#	Time	Username	Problem	Language	Result	Execution time	Memory
1211161		VMaksimoski008	Let's Win the Election (JOI22_ho_t3)	C++20	100 / 100	1386 ms	4164 KiB

Main

#include <bits/stdc++.h>
using namespace std;
using ll = long long;

int n, x, cnt=0;
vector<array<ll, 2> > a;
double dp[2][505][505];

double f(int c) {
    for(int i=0; i<2; i++)
        for(int j=0; j<=x-c; j++)
            for(int k=0; k<=c; k++)
                dp[i][j][k] = 1e18;
    dp[0][0][0] = 0;

    for(int i=1; i<=n; i++) {
        int p = i&1;
        for(int j=0; j<=x-c; j++) {
            for(int k=0; k<=c; k++) {
                dp[p][j][k] = dp[p^1][j][k];

                if(j)
                    dp[p][j][k] = min(dp[p][j][k], dp[p^1][j-1][k] + (double)a[i][1] / (1 + c));
                if(k && a[i][0] != -1)
                    dp[p][j][k] = min(dp[p][j][k], dp[p^1][j][k-1] + (double)a[i][0] / k);
            }
        }
    }
    return dp[n&1][x-c][c];
}

signed main() {
    cin >> n >> x;
    a.resize(n+1);

    for(int i=1; i<=n; i++) {
        cin >> a[i][1] >> a[i][0];
        if(a[i][0] != -1) cnt++;
    }
    sort(a.begin()+1, a.end());

    int l=0, r=min(x, cnt)-1, p = min(x, cnt);
    while(l <= r) {
        int mid = (l + r) / 2;
        if(f(mid) <= f(mid+1)) p = mid, r = mid - 1;
        else l = mid + 1;
    }
    cout << setprecision(3) << fixed << f(p) << '\n';
}

• 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