暴力 Codeforces Round #183 (Div. 2) A. Pythagorean Theorem II

 1 /*
 2     暴力：O (n^2)
 3 */
 4 #include <cstdio>
 5 #include <algorithm>
 6 #include <cstring>
 7 #include <cmath>
 8 #include <vector>
 9 using namespace std;
10 
11 const int MAXN = 1e4 + 10;
12 const int INF = 0x3f3f3f3f;
13 
14 int main(void)        //Codeforces Round #183 (Div. 2) A. Pythagorean Theorem II
15 {
16     int n;
17     while (scanf ("%d", &n) == 1)
18     {
19         int ans = 0;
20         for (int i=1; i<=n; ++i)
21         {
22             for (int j=i; j<=n; ++j)
23             {
24                 if (i * i + j * j > n * n)    break;
25                 int c = sqrt (i * i + j * j);
26                 if (c <= n && c * c == i * i + j * j)    ans++;
27             }
28         }
29 
30         printf ("%d\n", ans);
31     }
32 
33     return 0;
34 }