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validate_binary_search_tree.cpp
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validate_binary_search_tree.cpp
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/**
* Definition for a binary tree node.
* struct TreeNode {
* int val;
* TreeNode *left;
* TreeNode *right;
* TreeNode() : val(0), left(nullptr), right(nullptr) {}
* TreeNode(int x) : val(x), left(nullptr), right(nullptr) {}
* TreeNode(int x, TreeNode *left, TreeNode *right) : val(x), left(left), right(right) {}
* };
*/
class Solution {
public:
bool validate(TreeNode* root, TreeNode* low, TreeNode* high)
{
if(root == nullptr)
return true;
// левая часть должна быть меньше корня
if(low != nullptr)
{
if(root->val <= low->val)
return false;
}
// правая часть должна быть больше корня
if(high != nullptr)
{
if(root->val >= high->val)
return false;
}
return validate(root->right, root, high) && validate(root->left, low, root);
}
bool isValidBST(TreeNode* root) {
return validate(root, nullptr, nullptr);
}
};