UVA - 1393 Highways(枚举包围盒大小，包围盒只有对角线穿过两个点)

#include <cstdio>#include <cstring>#include <iostream>#include <algorithm>using namespace std;typedef long long LL;const int maxn =305;int m,n;int g[maxn][maxn];int gcd(int a,int b){return b==0 ? a : gcd(b,a%b);}void init(){  int lim = 300;  for(int i=1;i<=lim;i++)       for(int j=1;j<=lim;j++)           g[i][j] = gcd(i,j);}int main(){    init();    while(scanf("%d %d",&m,&n)==2){           if(!n&&!m) break;           LL res = 0;           for(int a=1;a<m;a++)              for(int b=1;b<n;b++){                 if(g[a][b] > 1) continue;                 res+=(m-a)*(n-b)-max(0,m-2*a)*max(0,n-2*b);           }           printf("%lld\n",res*2);    }    return 0;}