#include <iostream>
#include <vector>
#include <algorithm>
using namespace std;
typedef long long int lli;
int main() {
std::ios_base::sync_with_stdio(false);
std::cin.tie(nullptr);
int n;
cin >> n;
vector<int> squares(n+1);
for ( int i = 0; i <= n; ++i ) {
squares[i] = i*i;
}
int nn = squares[n];
vector<int> sqr_sum(nn + 1, 0);
for ( int i = 1; i <=n; ++i ) {
for ( int j = i, res; (res = j*j + i*i) <= nn; ++j ) {
sqr_sum[res]++;
}
}
int res = 0;
int i = *sqr_sum.end();
int j = sqr_sum[sqr_sum.size()-1];
for ( int d = 3; d <=n; ++d ) {
int dd = d*d;
for ( int h = 1; h < d; ++h ) {
int hh = h*h;
res += sqr_sum[dd-hh];
}
}
cout << res << "\n";
return 0;
}
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 | #include <iostream> #include <vector> #include <algorithm> using namespace std; typedef long long int lli; int main() { std::ios_base::sync_with_stdio(false); std::cin.tie(nullptr); int n; cin >> n; vector<int> squares(n+1); for ( int i = 0; i <= n; ++i ) { squares[i] = i*i; } int nn = squares[n]; vector<int> sqr_sum(nn + 1, 0); for ( int i = 1; i <=n; ++i ) { for ( int j = i, res; (res = j*j + i*i) <= nn; ++j ) { sqr_sum[res]++; } } int res = 0; int i = *sqr_sum.end(); int j = sqr_sum[sqr_sum.size()-1]; for ( int d = 3; d <=n; ++d ) { int dd = d*d; for ( int h = 1; h < d; ++h ) { int hh = h*h; res += sqr_sum[dd-hh]; } } cout << res << "\n"; return 0; } |
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