[111. Minimum Depth of Binary Tree] #leetcode

111_0823.java

class Solution {
  // O(n) O(n/h)
    public int minDepth(TreeNode root) {
        if (root == null) return 0;
        int left = minDepth(root.left);
        int right = minDepth(root.right);
        
        return (left == 0 || right == 0) ? left + right + 1: Math.min(left, right) + 1;
    }
}