A Simple Problem
Time Limit: 2000/1000 MS (Java/Others) Memory Limit: 65535/32768 K (Java/Others)
Total Submission(s): 5748 Accepted Submission(s): 1515
Then T line followed each containing an integer n (1<=n <= 10^9).
2
3
1
// y^2 = n +x^2.即 (y+x)(y-x) = n
//设 i = y-x, n/i = y+x , x = (n/k-k)%2 由于 x, y是正整数, 则 y,x不会等于0, 所以这边还有一点最重要的(y+x) (y-x) 不能相等
#include<iostream>
#include<algorithm>
#include<cmath>
using namespace std;
int main()
{
int t, n, i, flag, x;
cin >> t;
while(t--)
{
cin >> n;
flag = 0;
i = sqrt(n);
for(int k = i; k >=1; k--) //题意是求符合条件,最小的x, 所以 k 要从最大因子开始判断
{
if(n%k == 0 && (n/k-k)%2 == 0 && n/k != k) //控制好符合条件是最重要的
{
x = (n/k - k)/2;
cout << x << endl;
flag = 1;
break;
}
}
if(flag == 0)
{
cout << -1 << endl;
}
}
return 0;
}