#include<bits/stdc++.h>
using namespace std;
typedef long long ll;
typedef long double ld;
#define rep(a, b) for(int a = 0; a < (b); ++a)
#define st first
#define nd second
#define pb push_back
#define all(a) a.begin(), a.end()
const int LIM=5e3+7;
ll T[LIM*LIM];
int main() {
ios_base::sync_with_stdio(0); cin.tie(0);
ll n;
cin >> n;
for(ll a=1; a*a<=n*n; ++a) {
for(ll b=1; a*a+b*b<=n*n && b<=a; ++b) {
++T[a*a+b*b];
}
}
ll ans=0;
for(ll x=1; x<=n; ++x) {
for(ll y=1; y<x; ++y) {
ans+=T[x*x-y*y];
}
}
cout << ans << '\n';
}
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 | #include<bits/stdc++.h> using namespace std; typedef long long ll; typedef long double ld; #define rep(a, b) for(int a = 0; a < (b); ++a) #define st first #define nd second #define pb push_back #define all(a) a.begin(), a.end() const int LIM=5e3+7; ll T[LIM*LIM]; int main() { ios_base::sync_with_stdio(0); cin.tie(0); ll n; cin >> n; for(ll a=1; a*a<=n*n; ++a) { for(ll b=1; a*a+b*b<=n*n && b<=a; ++b) { ++T[a*a+b*b]; } } ll ans=0; for(ll x=1; x<=n; ++x) { for(ll y=1; y<x; ++y) { ans+=T[x*x-y*y]; } } cout << ans << '\n'; } |
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