打表找规律eee
#include<cstdio> using namespace std; typedef long long ll; ll p,q; //int main() //{ // ios::sync_with_stdio(false); // int p,q; // while(1) // {cin>>p>>q; // ll sum1=0,sum2=0,m=p/2,n=q/2; // for(int i=1;i<=m;i++) // sum1+=i*q/p; // for(int j=1;j<=n;j++) // sum2+=j*p/q; // cout<<sum1<<" "<<sum2<<" "<<sum1+sum2;} //}//打表 inline void read(long long &x) { x = 0;char ch = getchar(), c = ch; while(ch < '0' || ch > '9') c = ch, ch = getchar(); while(ch <= '9' && ch >= '0') x = x * 10 + ch - '0', ch = getchar(); if(c == '-') x = -x; } int main() { read(p),read(q); if(p==q) printf("%lld",(p-1)*(q+1)>>2); else printf("%lld",(p-1)*(q-1)>>2); return 0; }
特判p==q eee