MinDepth of a tree

MinDepth.java

package com.interviewbytes.trees;

public class MinDepth {

    public int minDepth(TreeNode root) {

        if (root == null) return 0;

        if (root.left == null && root.right == null) return 1;
        if (root.left == null || root.right == null) return 1 + minDepth(root.left) + minDepth(root.right);

        return 1 + Math.min(minDepth(root.left), minDepth(root.right));
    }
}

TreeNode.java

package com.interviewbytes.trees;

public class TreeNode {

    int val;
    TreeNode left;
    TreeNode right;

    TreeNode(int x) {
        val = x;
    }
}