Submission #1027333

#	Time	Username	Problem	Language	Result	Execution time	Memory
1027333		vjudge1	Sure Bet (CEOI17_sure)	C++14	100 / 100	106 ms	11348 KiB

sure

#include<bits/stdc++.h>
#define ll long long int
#define pb push_back
#define yy cout<<"YES"<<endl;
#define nn cout<<"NO"<<endl;
#define ld long double
#define T ll t;cin>>t;while(t--){solve();}
#define funfact for(ll i=1 ; i<=n ; i++){cout<<a[i]<<" ";}
using namespace std;
const ll N=2e5,mod=1e9+7,inf=1e18;
ld a[N],b[N];
ld prea[N],preb[N];
ll n;
//----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------//
bool cmp (ld x,ld y)
{
    return x>y;
}
ld f(ll x,ll y)
{
    return min(prea[x]-1.0*y,preb[y]-1.0*x);
}
ld bin(ll x)
{
    ll l=1,r=n;
    ld ans=-1;
    if(n == 1) return f(x, 1);
	if(n == 2) return max(f(x, 1), f(x, 2));
    while (l<=r)
    {
        ll md=(l+r)/2;
        ll fi=md-1,se=md,th=md+1;
        if (fi==0)
        {
            ans=md,l=md+1;
            continue;
        }
        if (th==n+1)
        {
            ans=md,r=md-1;
            //continue;
        }
        if (f(x,fi)<=f(x,se)&&f(x,se)<=f(x,th))
        {
            ans=md+1,l=md+1;
        }
        else if (f(x,fi)>=f(x,se)&&f(x,se)>=f(x,th))
        {
            ans=md-1,r=md-1;
        }
        else if (f(x,fi)<=f(x,se)&&f(x,se)>=f(x,th))
        {
            return f(x,se);
        }
    }
    return f(x,ans);
}
void solve(){
    cin>>n;
    for (ll i=1;i<=n;i++)
    {
        cin>>a[i]>>b[i];
        a[i]--;
        b[i]--;
    }
    sort(a+1,a+n+1,cmp);
    sort(b+1,b+n+1,cmp);
    ld ans=0.0;
    for (ll i=1;i<=n;i++){
        prea[i]+=prea[i-1]+a[i];
        preb[i]+=preb[i-1]+b[i];}
    for (ll i=n;i>=1;i--)
    {
        ans=max(ans,bin(i));
    }
    cout<<fixed<<setprecision(4)<<ans<<endl;
}
int main(){
    ios_base::sync_with_stdio(false);
    cin.tie(0);
    solve();
}
/* This code is created by anhluong
-------Copy code is prohibiited in any form
--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
*/

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