Minimum Depth of Binary Tree

Problem:

Given a binary tree, find its minimum depth.

The minimum depth is the number of nodes along the shortest path from the root node down to the nearest leaf node.

Solution:

/**
 * Definition for binary tree
 * public class TreeNode {
 *     int val;
 *     TreeNode left;
 *     TreeNode right;
 *     TreeNode(int x) { val = x; }
 * }
 */
public class Solution {
    public int minDepth(TreeNode root) {
        if(root==null)
             return 0;
        if(root.left==null&&root.right==null)
             return 1;
        else if(root.left==null)
             return minDepth(root.right)+1;
        else if(root.right==null)
             return minDepth(root.left)+1;
        else
             return Math.min(minDepth(root.left),minDepth(root.right))+1;     
    }
}