Submission #1042761

#	Time	Username	Problem	Language	Result	Execution time	Memory
1042761		fryingduc	Sure Bet (CEOI17_sure)	C++17	100 / 100	55 ms	4436 KiB

sure

//#pragma GCC optimize("Ofast,unroll-loops") 
#include "bits/stdc++.h"
using namespace std;

#ifdef duc_debug
#include "bits/debug.h"
#else 
#define debug(...)     
#endif

//#define int long long

const int maxn = 1e5+5;
int n;
double a[maxn], b[maxn];
double ps[maxn];

int check(int mid, int argentina, double sum){
    double left = min(sum - argentina + 1, ps[n] - ps[n - mid + 1] - argentina + 1);
    double right = min(sum - argentina - 1, ps[n] - ps[n - mid - 1] - argentina - 1);
    double cur = min(sum - argentina, ps[n] - ps[n -  mid] - argentina);
    if(cur > left and cur > right) return 0;
    else{
        if(cur < left) return 2;
        else return 1;
    }
}

void solve(){
    cin >> n;
    for(int i = 1; i <= n; ++i){
        cin >> a[i] >> b[i];
    }
    sort(a + 1, a + n + 1);
    sort(b + 1, b + n + 1);
    ps[n + 1] = 0;
    for(int i = 1; i <= n; ++i){
        ps[i] = ps[i - 1] + b[i];
    }
    double ans = 0, sum = 0;
    for(int i = n; i; --i){
        sum += a[i];
        int l = 1, r = n;
        while(l <= r){
            int mid = (l + r) / 2;
            int argentina = (n - i + 1) + mid;
            if(check(mid, argentina, sum) == 1){
                l = mid + 1;
            }
            else if(check(mid, argentina, sum) == 2){
                r = mid - 1;
            }
            else{
                ans = max(ans, min(sum - argentina, ps[n] - ps[n - mid] - argentina));
                break;
            }
            debug(i, mid, ans);
        }
        // ans = max(ans, rodi);
    }
    cout << fixed << setprecision(4) << ans;
}
signed main(){
    ios_base::sync_with_stdio(0);
    cin.tie(0);

    int test = 1;
    // cin >> test;
    for(int i = 1; i <= test; i++){
      // cout << "Case " << "#" << i << ": "; 
      solve();
    }

    return 0;
}

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