#include <iostream> #include <algorithm> const int MAX = 5000+2; int SC[MAX*MAX*2]; void init(int n) { for (int i=1;i<=n;++i) { for (int j=i;j<=n;++j) { SC[i*i+j*j]++; } } } int main() { std::ios_base::sync_with_stdio(0); int n; std::cin >> n; init(n); int64_t c = 0; for (int i=1;i<=n;++i) { int sc = i*i; for (int h=1;h<i;++h) { c += SC[sc-h*h]; } } std::cout << c << std::endl; 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 | #include <iostream> #include <algorithm> const int MAX = 5000+2; int SC[MAX*MAX*2]; void init(int n) { for (int i=1;i<=n;++i) { for (int j=i;j<=n;++j) { SC[i*i+j*j]++; } } } int main() { std::ios_base::sync_with_stdio(0); int n; std::cin >> n; init(n); int64_t c = 0; for (int i=1;i<=n;++i) { int sc = i*i; for (int h=1;h<i;++h) { c += SC[sc-h*h]; } } std::cout << c << std::endl; return 0; } |