bool is_same_tree (bst* p, bst* q) {
if (p && q) {
//return (value_cmp && structure_cmp)
return ( p->val == q->val
&& (is_same_tree (p->left,q->left))
&& (is_same_tree (p->right,q->right)) );
} else if (p != 0 || q != 0) {
return false;
}
}
bool is_same_tree(TreeNode* atree, TreeNode* btree) {
if (!atree and !btree) {
return true;
}
if (!atree or !btree) {
return false;
}
if (atree->value != btree->value) {
return false;
}
return is_same_tree(atree->left, btree->left) and
is_same_tree(atree->right, btree->right);
}
bool is_subtree(TreeNode* head, TreeNode* sub_head) {
if (!sub_head) {
return true;
}
if (!head) {
return false;
}
stack<TreeNode* > stk;
stk.push(head);
while (stk.size()) {
TreeNode* cur = stk.top();
stk.pop();
if (is_same_tree(cur, sub_head)) {
return true;
}
if (cur->left) {
stk.push(cur->left);
}
if (cur->right) {
stk.push(cur->right);
}
}
return false;
}
