Submission #445737

#	Time	Username	Problem	Language	Result	Execution time	Memory
445737		Nima_Naderi	Sure Bet (CEOI17_sure)	C++14	100 / 100	219 ms	14576 KiB

sure

///In the name of GOD
//#pragma GCC optimize("O2")
#include<bits/stdc++.h>
using namespace std;

typedef long long ll;
typedef long double ld;
const ll MXN = 3e5 + 10;
const ld EPS = 1e-9;
ll n;
ld A[MXN], B[MXN], psa[MXN], psb[MXN], ans;
ld Cal(ll x, ll y){
    return min(psa[x], psb[y]) - x - y;
}
ld Calc(){
    for(int i = 1; i <= n; i ++){
        psa[i] = psa[i - 1] + A[i];
        psb[i] = psb[i - 1] + B[i];
    }
    for(int i = 1; i <= n; i ++){
        ll l = 0, r = n;
        ans = max(ans, Cal(i, l));
        ans = max(ans, Cal(i, r));
        while(r - l > 10){
            ll tid1 = (l * 2 + r) / 3;
            ll tid2 = (l + r * 2) / 3;
            ld nw1 = Cal(i, tid1);
            ld nw2 = Cal(i, tid2);
            ans = max(ans, nw1);
            ans = max(ans, nw2);
            if(nw1 > nw2) r = tid2;
            else          l = tid1;
        }
        for(int j = l; j <= r; j ++){
            ans = max(ans, Cal(i, j));
        }
    }
    return ans;
}
int main(){
    ios::sync_with_stdio(0);cin.tie(0); cout.tie(0);
    cin >> n;
    for(int i = 1; i <= n; i ++) cin >> A[i] >> B[i];
    sort(A + 1, A + n + 1, greater<ld>());
    sort(B + 1, B + n + 1, greater<ld>());
    ans = max(ans, Calc());
    swap(A, B);
    ans = max(ans, Calc());
    cout << fixed << setprecision(4) << ans << '\n';
    return 0;
}
/*!
    HE'S AN INSTIGATOR,
    ENEMY ELIMINATOR,
    AND WHEN HE KNOCKS YOU BETTER
    YOU BETTER LET HIM IN.
*/
//! N.N

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