Count Nodes Equal to Average of Subtree LeetCode solution in Java

1
class Solution {
2
  int res = 0;
3

4
  public int averageOfSubtree(TreeNode root) {
5
    dfs(root);
6
    return res;
7
  }
8

9
  private int[] dfs(TreeNode node) {
10
    if (node == null) {
11
      return new int[] {0, 0};
12
    }
13

14
    int[] left = dfs(node.left);
15
    int[] right = dfs(node.right);
16

17
    int currSum = left[0] + right[0] + node.val;
18
    int currCount = left[1] + right[1] + 1;
19

20
    if (currSum / currCount == node.val) {
21
      res++;
22
    }
23

24
    return new int[] {currSum, currCount};
25
  }
26
}