力扣leetcode 111. 二叉樹的最小深度 java

/**
 * Definition for a binary tree node.
 * public class TreeNode {
 *     int val;
 *     TreeNode left;
 *     TreeNode right;
 *     TreeNode(int x) { val = x; }
 * }
 */
class Solution {
    public int min(int a, int b) { return a < b ? a : b; }
    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 min(minDepth(root.left), minDepth(root.right)) + 1;
    }
}