Submission #1282194

#	Time	Username	Problem	Language	Result	Execution time	Memory
1282194		swishy123	Sure Bet (CEOI17_sure)	C++20	100 / 100	631 ms	6716 KiB

sure

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

using namespace std;

const int def = 1e6+1;
const int maxk = 18;
const ll inf = 1e18;
const ld eps = 1e-9;

void solve(){
    int n;
    cin >> n;

    vector<ld> a(n);
    auto b = a;

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

    sort(a.begin(), a.end(), greater<ld>());
    sort(b.begin(), b.end(), greater<ld>());

    vector<ld> prefa(n + 1, 0);
    auto prefb = prefa;

    for (int i = 1; i <= n; i++){
        prefa[i] = prefa[i - 1] + a[i - 1];
        prefb[i] = prefb[i - 1] + b[i - 1];
    }

    ld res = 0;
    for (int i = 1; i <= 2 * n; i++){
        ld l = 0, r = min(prefa[n], prefb[n]), mid = (l + r) / 2;
        while (r - l > eps){
            int cnt1 = lower_bound(prefa.begin(), prefa.end(), mid) - prefa.begin();
            int cnt2 = lower_bound(prefb.begin(), prefb.end(), mid) - prefb.begin();

            if (cnt1 + cnt2 > i)
                r = mid;
            else    
                l = mid;
            mid = (l + r) / 2;
        }
        res = max(res, l - i);
    }
    cout << setprecision(4) << fixed << res;
}

/*
0 0 0 0 0
*/

main(){
    ios_base::sync_with_stdio(0);
    cin.tie(0); cout.tie(0);

    if (ifstream("input.txt").good()){
        freopen("input.txt", "r", stdin);
        freopen("output.txt", "w", stdout); 
    }

    int t = 1;
    while (t--){
        solve();
        cout << "\n";
    }
}

Compilation message (stderr)

sure.cpp:55:1: warning: ISO C++ forbids declaration of 'main' with no type [-Wreturn-type]
   55 | main(){
      | ^~~~
sure.cpp: In function 'int main()':
sure.cpp:60:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   60 |         freopen("input.txt", "r", stdin);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~
sure.cpp:61:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   61 |         freopen("output.txt", "w", stdout);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~

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