/in/foo.cc: In function 'int main()':
/in/foo.cc:21:76: warning: suggest parentheses around '-' inside '<<' [-Wparentheses]
  rep(j,1,18) for(int i=1;i+(1<<j)-1<=n;i++) f[i][j]=max(f[i][j-1],f[i+(1<<j-1)][j-1]);
                                                                           ~^~