Submission #43958

#	Time	Username	Problem	Language	Result	Execution time	Memory
43958		desert97	Sure Bet (CEOI17_sure)	C++14	100 / 100	284 ms	2364 KiB

sure

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

const int MAXN = 1e5+5;

double a[MAXN], b[MAXN];
int n;

bool check(double x) {
    int l = n, r = n;
    double totl = 0, totr = 0;

    for (int k = 1; k <= 2*n; ++k) {
        if (totl < k+x) {
            if (l == 0)
                break;
            l--;
            totl += a[l];
        } if (totr < k+x) {
            if (r == 0)
                break;
            r--;
            totr += b[r];
        }

        if (n-l+n-r <= k)
            return 1;
    }

    return 0;
}

int main() {
    cin >> n;
    for (int i = 0; i < n; ++i)
        cin >> a[i] >> b[i];
    sort(a, a+n);
    sort(b, b+n);

    double lo = 0, hi = 1e15;
    for (int i = 0; i <= 200; ++i) {
        double mid = (lo+hi)/2;
        if (check(mid))
            lo = mid;
        else
            hi = mid;
    }

    cout << fixed << setprecision(4) << lo << endl;
}

• Subtask 1: 20 / 20
• Subtask 2: 40 / 40
• Subtask 3: 40 / 40