Leetcode

Count Good Nodes in Binary Tree

May 26, 2022 by aAshish

  • Time:O(n)
  • Space:O(h)

C++

 
class Solution {
 public:
  int goodNodes(TreeNode* root, int maxi = INT_MIN) {
    if (!root)
      return 0;

    const int newMax = max(maxi, root->val);
    return (root->val >= maxi) +
           goodNodes(root->left, newMax) +
           goodNodes(root->right, newMax);
  }
};

JAVA

 
class Solution {
  public int goodNodes(TreeNode root) {
    return goodNodes(root, Integer.MIN_VALUE);
  }

  private int goodNodes(TreeNode root, int max) {
    if (root == null)
      return 0;

    final int newMax = Math.max(max, root.val);
    return (root.val >= max ? 1 : 0) + goodNodes(root.left, newMax) + goodNodes(root.right, newMax);
  }
}