题解 | #牛群的最短路径#

import java.util.*;

/*
 * public class TreeNode {
 *   int val = 0;
 *   TreeNode left = null;
 *   TreeNode right = null;
 *   public TreeNode(int val) {
 *     this.val = val;
 *   }
 * }
 */

public class Solution {
    /**
     * 代码中的类名、方法名、参数名已经指定，请勿修改，直接返回方法规定的值即可
     *
     * 
     * @param root TreeNode类 
     * @return int整型
     */
    public static int min_depth = 1000;
    public int minDepth (TreeNode root) {
        // write code here
        if(root== null){
            return 0;
        }
        search(root,1);
        return min_depth;
    }

    public void search(TreeNode root,int level){
        if(root.left == null && root.right == null){
            min_depth = Math.min(min_depth,level);
            return;
        }

        if(root.left != null){
            search(root.left,level + 1);
        }
        
        if(root.right != null){
            search(root.right,level + 1);
        }
    }
}