Given a binary tree root, a node X in the tree is named good if in the path from root to X there are no nodes with a value greater than X.
Return the number of good nodes in the binary tree.
Example 1:
Input: root = [3,1,4,3,null,1,5] Output: 4 Explanation: Nodes in blue are good. Root Node (3) is always a good node. Node 4 -> (3,4) is the maximum value in the path starting from the root. Node 5 -> (3,4,5) is the maximum value in the path Node 3 -> (3,1,3) is the maximum value in the path.
Example 2:
Input: root = [3,3,null,4,2] Output: 3 Explanation: Node 2 -> (3, 3, 2) is not good, because "3" is higher than it.
Example 3:
Input: root = [1] Output: 1 Explanation: Root is considered as good.
Constraints:
[1, 10^5].[-10^4, 10^4].
class Solution {
public:
void countGood(TreeNode* root, int &count, int currMax)
{
if(!root)return;
if(root->val>=currMax)
{
count++;
currMax=root->val;
}
countGood(root->left, count, currMax);
countGood(root->right, count, currMax);
}
int goodNodes(TreeNode* root) {
int count=0;
countGood(root,count,INT_MIN);
return count;
}
};
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