#include<bits/stdc++.h> using namespace std; #define ll long long inline int read(){ int s=0,w=1; char ch=getchar(); while(ch<'0'||ch>'9'){if(ch=='-')w=-1;ch=getchar();} while(ch>='0'&&ch<='9') s=s*10+ch-'0',ch=getchar(); return s*w; } int f[25000003]; signed main() { int n=read(); ll ans=0; n=n*n; for(int i=1; i*i<=n; ++i) for(int j=1; j<i; ++j) ++f[(i-j)*(i+j)]; for(int i=1; i*i*2<n; ++i) for(int j=i; i*i+j*j<n; ++j) ans+=f[i*i+j*j]; printf("%lld\n",ans); 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 | #include<bits/stdc++.h> using namespace std; #define ll long long inline int read(){ int s=0,w=1; char ch=getchar(); while(ch<'0'||ch>'9'){if(ch=='-')w=-1;ch=getchar();} while(ch>='0'&&ch<='9') s=s*10+ch-'0',ch=getchar(); return s*w; } int f[25000003]; signed main() { int n=read(); ll ans=0; n=n*n; for(int i=1; i*i<=n; ++i) for(int j=1; j<i; ++j) ++f[(i-j)*(i+j)]; for(int i=1; i*i*2<n; ++i) for(int j=i; i*i+j*j<n; ++j) ans+=f[i*i+j*j]; printf("%lld\n",ans); return 0; } |