#include <bits/stdc++.h> using namespace std; #define rep(i,a,n) for (int i=(a);i<(n);i++) #define per(i,a,n) for (int i=(n)-1;i>=(a);i--) #define pb push_back #define eb emplace_back #define mp make_pair #define all(x) (x).begin(),(x).end() #define fi first #define se second #define SZ(x) ((int)(x).size()) typedef vector<int> VI; typedef basic_string<int> BI; typedef long long ll; typedef pair<int,int> PII; typedef long double db; mt19937 mrand(1111); const ll mod=1000000007; int rnd(int x) { return mrand() % x;} ll powmod(ll a,ll b) {ll res=1;a%=mod; assert(b>=0); for(;b;b>>=1){if(b&1)res=res*a%mod;a=a*a%mod;}return res;} ll gcd(ll a,ll b) { return b?gcd(b,a%b):a;} // head const int N=5010; int c[N*N],n; ll ans; int main() { scanf("%d",&n); for (int i=1;i<=n;i++) for (int j=i;i*i+j*j<n*n;j++) { c[i*i+j*j]+=1; } for (int i=1;i<=n;i++) for (int j=1;j<i;j++) ans+=c[i*i-j*j]; printf("%lld\n",ans); }
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 | #include <bits/stdc++.h> using namespace std; #define rep(i,a,n) for (int i=(a);i<(n);i++) #define per(i,a,n) for (int i=(n)-1;i>=(a);i--) #define pb push_back #define eb emplace_back #define mp make_pair #define all(x) (x).begin(),(x).end() #define fi first #define se second #define SZ(x) ((int)(x).size()) typedef vector<int> VI; typedef basic_string<int> BI; typedef long long ll; typedef pair<int,int> PII; typedef long double db; mt19937 mrand(1111); const ll mod=1000000007; int rnd(int x) { return mrand() % x;} ll powmod(ll a,ll b) {ll res=1;a%=mod; assert(b>=0); for(;b;b>>=1){if(b&1)res=res*a%mod;a=a*a%mod;}return res;} ll gcd(ll a,ll b) { return b?gcd(b,a%b):a;} // head const int N=5010; int c[N*N],n; ll ans; int main() { scanf("%d",&n); for (int i=1;i<=n;i++) for (int j=i;i*i+j*j<n*n;j++) { c[i*i+j*j]+=1; } for (int i=1;i<=n;i++) for (int j=1;j<i;j++) ans+=c[i*i-j*j]; printf("%lld\n",ans); } |