View Compilation Error

0_0_26090763_7887.cpp: In function 'void update(int, int, int)':
0_0_26090763_7887.cpp:47:21: error: 'r' was not declared in this scope
     if (tree[k].l > r || tree[k].r < l) return 0;
                     ^
0_0_26090763_7887.cpp:47:38: error: 'l' was not declared in this scope
     if (tree[k].l > r || tree[k].r < l) return 0;
                                      ^
0_0_26090763_7887.cpp:47:48: error: return-statement with a value, in function returning 'void' [-fpermissive]
     if (tree[k].l > r || tree[k].r < l) return 0;
                                                ^