goodNodes.java

/**
 * Definition for a binary tree node.
 * public class TreeNode {
 *     int val;
 *     TreeNode left;
 *     TreeNode right;
 *     TreeNode() {}
 *     TreeNode(int val) { this.val = val; }
 *     TreeNode(int val, TreeNode left, TreeNode right) {
 *         this.val = val;
 *         this.left = left;
 *         this.right = right;
 *     }
 * }
 */

class Solution {
    public int goodNodes(TreeNode root) {
        return dfs(root,root.val);
    }

    private int dfs(TreeNode root,int val){
        if(root == null) return 0;

        int c = 0;
        if(root.val >= val){
            c = 1;
            val = root.val;
        }

        c += dfs(root.left,val);
        c += dfs(root.right,val);
    
        return c;
    }
}