/in/foo.cc: In function 'void updata(int, int, int)':
/in/foo.cc:25:43: error: 'max' was not declared in this scope
 tree[i].ws=max(tree[i*2].ws,tree[i*2+1].ws);
                                           ^
/in/foo.cc: In function 'int main()':
/in/foo.cc:103:11: warning: unused variable 'j' [-Wunused-variable]
 int n,q,i,j,k;
           ^