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.
/** * 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) { // Note: The Solution object is instantiated only once and is reused by each test case. if(root==null){ return 0; } else if(root.left==null&&root.right==null){ return 1; } else if(root.left==null&&root.right!=null){ return 1+minDepth(root.right); } else if(root.left!=null&&root.right==null){ return 1+minDepth(root.left); } else { return minDepth(root.left)>minDepth(root.right)?1+minDepth(root.right):1+minDepth(root.left); } } }