LeetCode-111-Minimum Depth of Binary Tree(二叉树的最短路径)

Q:

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.

Analysis:

此题要求返回二叉树根结点到叶子结点最短的距离。

可以采用递归的方法：

Code:

/**
* Definition for a binary tree node.
* 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;
}
if (root.left == null) {
return minDepth(root.right) + 1;
}
if (root.right == null) {
return minDepth(root.left) + 1;
}
return Math.min(minDepth(root.left), minDepth(root.right)) + 1;
}
}