Minimum Depth of Binary Tree

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) {
        if(root == null)
            return 0;
        return depthOfTree(root);
    }
    public int depthOfTree(TreeNode root){
        if(root.left == null && root.right == null){//叶子节点
            return 1;
        }
        int left = 0;
        if(root.left != null)
            left = depthOfTree(root.left);
        int right = 0;
        if(root.right != null)
            right = depthOfTree(root.right);
        if(left != 0 && right != 0)
            return 1 + (left < right ? left : right);
        else if(left != 0)
            return 1 + left;
        else 
            return 1 + right;
    }
}

Runtime: 257 ms

Minimum Depth of Binary Tree

原文：http://blog.csdn.net/havedream_one/article/details/42557957