Enhanced the last debug functionality

tree_alloc.c

@@ -18,6 +18,9 @@ void debug_print_tree(int indent, void *p) {
   TreeAlloc *node = (TreeAlloc*) p;
   if (node != NULL) {
     int bad = debug_tree_black_height(node->left) != debug_tree_black_height(node->right);
+    bad |= node->color == COLOR_RED && ((node->left != NULL && node->left->color == COLOR_RED) ||
+        (node->right != NULL && node->right->color == COLOR_RED) || (node->parent != NULL &&
+          node->parent->color == COLOR_RED));
     debug_print_tree(indent + 1, node->left);
     for (int ii = 0; ii < indent; ii++) { printf("  "); }
     if (node->color == COLOR_RED) { printf("\e[31m"); }