Trees in a Wood UVA - 10214 欧拉函数模板

太坑惹,,,没用longlong各种WA

 #include <iostream>
 #include <string.h>
 #include <cstdio>
 #include <math.h>
 #define SIGMA_SIZE 26
 #pragma warning ( disable : 4996 )

 using namespace std;
 typedef long long LL;

 inline int Max(int a,int b) { return a>b?a:b; }
 inline int Min(int a,int b) { return a>b?b:a; }
 const int inf = 0x3f3f3f3f;
 const int maxn = 2e3+;
 const int maxk = 2e6+;

 int gcd(int a, int b)
 { return b==?a:gcd(b,a%b); }
 int A, B;
 int oula[maxn];
 bool g[maxn][maxn];

 void init()
 {
     memset( g, false, sizeof(g) );
     int i, j;
     for ( i = ; i < maxn; i++ )
         oula[i] = i;

     for ( i = ; i < maxn; i++ )
         if ( oula[i] == i )
             for ( j = i; j < maxn; j+=i )
                 oula[j] = oula[j]/i*(i-);

     for( i = ; i < maxn; i++ )
         for( j = ; j < maxn; j++ )
             if( gcd(i,j) ==  )
                 g[i][j] = true;
 }

 int main()
 {
     init();
     while ( ~scanf("%d%d", &A, &B)&&A&&B )
     {
         if( A > B ) swap(A,B);
         double sum = ;

         for ( int i = ; i <= A; i++ )
         {
             sum += oula[i]*(B/i);
             int tmp = B%i;
             for( int j = ; j <= tmp; j++ )
                 if ( g[i][j] )
                     sum++;
         }

         double ans = sum* + ;
         double all = (unsigned long long)A*B*+A+B;
         printf( "%.7lf\n", ans/all );
     }

     return ;
 }