poj 2975 Nim

Nim博弈题：这个题是要你求如果先手能赢，有几种策略；

#include<iostream>
 #include<cstdio>
 #include<cstdlib>
 #include<algorithm>
 #include<cmath>
 #include<queue>
 #include<set>
 #include<map>
 #include<cstring>
 #include<vector>
 #include<string>
 #define LL long long
 using namespace std;
 
 int main(  )
 {
    int n,num[1024];
    while( scanf( "%d",&n ),n )
    {
        int s = 0;
        for( int i = 0 ; i < n ;i ++ )
        {
              scanf( "%d",&num[i] );
              s ^= num[i];    
         }
         int ans = 0;
         if( s != 0 )
         for( int i = 0 ; i < n ; i ++ )
         {
             if( num[i] > (s^num[i])  ) ans++;
         }        
         printf( "%d\n",ans );
    }
     //system( "pause" );
     return 0;
 }