/in/foo.cc: In function 'int solve2(int)':
/in/foo.cc:35:26: warning: integer overflow in expression [-Woverflow]
     int s1,s2,ans=(1<<31)-1;
                   ~~~~~~~^~
/in/foo.cc:43:45: error: 'memset' was not declared in this scope
             memset(judge,false,sizeof(judge));//标记已用 
                                             ^