【HDU - 4342】History repeat itself（数学）

#include <cstdio>
#include <cmath>
#define ll long long
int t;
const int N=1LL<<16;
ll n,x,ans,a[N];
int main(){
	for(int i=1;i<=N;i++)
		a[i]=a[i-1]+(ll)(i*2+1)*i;
	scanf("%d", &t);
	while(t--){
		scanf("%lld", &n);
		ll l=1, r=1LL<<32;
		while(l<r){
			ll m=l+r>>1;
			if(m-(ll)sqrt(m)<n)
				l=m+1;
			else
				r=m;
		}
		x=l;
		ll g=floor(sqrt(x));
		ans=a[(int)g-1]+(x-g*g+1)*g;
		printf("%lld %lld\n", x, ans);
	}
	return 0;
}