1
 2
 3
 4
 5
 6
 7
 8
 9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
#include <iostream>
#include <vector>
using namespace std;

int main() {
    int n;
    cin >> n;
    ios::sync_with_stdio(0);
    cin.tie(0);
    int maxi = 24999999; 
    vector<int> tab(maxi + 1, 0);
    for (int y = 1; y <= 5000; y++) {
        for (int i = y; i <= 5000; i++) {
            int s = y * y + i * i;
            if (s > maxi) break;
            tab[s]++;
        }
    }
    int result = 0;
    for (int k = 1; k <= n; k++) {
        for (int h = 1; h < k; h++) {
            int s = k * k - h * h;
            if (s < 2 or s > maxi) continue;
            result += tab[s];
        }
    }
    cout << result;
    return 0;
}