/in/foo.cc: In function 'int main()':
/in/foo.cc:21:17: warning: iteration 9999 invokes undefined behavior [-Waggressive-loop-optimizations]
        f[j]&=g[j];//&的意义：1&1=1，1&0=0 用于求共同
                 ^
/in/foo.cc:20:16: note: within this loop
       for(j=1;j<=10000;j++)
               ~^~~~~~~