Educational Codeforces Round 24 F. Level Generation(三分)

 1 #include<bits/stdc++.h>
 2 #define F(i,a,b) for(int i=(a);i<=(b);++i)
 3 using namespace std;
 4 typedef long long ll;
 5 
 6 int q;
 7 ll n,ans;
 8 
 9 ll check(ll mid)
10 {
11     ll tmp=(mid*mid-mid)/2;
12     if(n-mid>=tmp)return tmp+n-mid;
13     else if(n-mid>=mid-1)return (n-mid)*2;
14     else return mid-1;
15 }
16 
17 int main(){
18     scanf("%d",&q);
19     while(q--)
20     {
21         scanf("%I64d",&n);
22         ll l,r,mid,mmid;
23         for(l=1,r=n;l<r-1;)
24         {
25             mid=l+r>>1,mmid=mid+r>>1;
26             if(check(mid)>check(mmid))r=mmid;
27             else l=mid;
28         }
29         printf("%I64d\n",max(check(l),max(check(r),check(1))));
30     }
31     return 0;
32 }