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
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
#include <bits/stdc++.h>
 
using namespace std;
 
#define endl '\n'
#define L long long
#define MP make_pair
#define REP(i, n) for(int i = 0; i < n; ++i)
#define REPR(i, n) for(int i = n - 1; i >= 0; --i)
#define FOR(i, a, b) for(int i = a; i < b; ++i)
#define FORR(i, a, b) for(int i = b - 1; i >= a; --i)
#define EB emplace_back
#define ST first
#define ND second
#define S size
#define RS resize
 
template<class T> using P = pair<T, T>;
template<class T> using V = vector<T>;
 
int main() {
    ios_base::sync_with_stdio(0);
    cin.tie(0);

    int n;
    cin >> n;

    V<int> count(n * n + 1);
    FOR(a, 1, n + 1) {
        FOR(b, a, n + 1) {
            int c = a * a + b * b;
            if (c <= n * n) {
                count[c]++;
            }
        }
    }

    int res = 0;
    FOR(d, 1, n + 1) {
        FOR(h, 1, d) {
            res += count[d * d - h * h];
        }
    }

    cout << res << '\n';
}

// g++ -std=c++20 -Wall -Wextra -Wshadow -Wconversion -D_GLIBCXX_DEBUG akw.cpp -o akw