/in/foo.cc: In function 'void work()':
/in/foo.cc:56:31: warning: suggest parentheses around '-' inside '<<' [-Wparentheses]
         if(f[i][j-1]<f[i+(1<<j-1)][j-1])
                              ~^~
/in/foo.cc:58:31: warning: suggest parentheses around '-' inside '<<' [-Wparentheses]
         else f[i][j]=f[i+(1<<j-1)][j-1],rec[i][j]=rec[i+(1<<j-1)][j-1];
                              ~^~
/in/foo.cc:58:62: warning: suggest parentheses around '-' inside '<<' [-Wparentheses]
         else f[i][j]=f[i+(1<<j-1)][j-1],rec[i][j]=rec[i+(1<<j-1)][j-1];
                                                             ~^~