// @Title: 二叉树的最小深度 (Minimum Depth of Binary Tree)
// @Author: qisiii
// @Date: 2024-09-14 23:42:57
// @Runtime: 10 ms
// @Memory: 61.4 MB
// @comment: 
// @flag: 
/**
 * Definition for a binary tree node.
 * public class TreeNode {
 * int val;
 * TreeNode left;
 * TreeNode right;
 * TreeNode() {}
 * TreeNode(int val) { this.val = val; }
 * TreeNode(int val, TreeNode left, TreeNode right) {
 * this.val = val;
 * this.left = left;
 * this.right = right;
 * }
 * }
 */
class Solution {
    public int minDepth(TreeNode root) {
        if (root == null) {
            return 0;
        }
        int left = minDepth(root.left);
        int right = minDepth(root.right);
        // 如果左子树或者右子树为0，那得以不为空的那棵树为准
        if (left == 0 || right == 0) {
            return left + right + 1;
        }
        return Math.min(left, right) + 1;
    }
}

// @Title: 二叉树的最小深度 (Minimum Depth of Binary Tree)
// @Author: qisiii
// @Date: 2024-01-14 19:59:44
// @Runtime: 14 ms
// @Memory: 62 MB
// @comment: 
// @flag: 
/**
 * Definition for a binary tree node.
 * public class TreeNode {
 *     int val;
 *     TreeNode left;
 *     TreeNode right;
 *     TreeNode() {}
 *     TreeNode(int val) { this.val = val; }
 *     TreeNode(int val, TreeNode left, TreeNode right) {
 *         this.val = val;
 *         this.left = left;
 *         this.right = right;
 *     }
 * }
 */
class Solution {
    public int minDepth(TreeNode root) {
        if(root==null){
            return 0;
        }
        int left=minDepth(root.left);
        int right=minDepth(root.right);
        if(left==0){
            return 1+right;
        }
        if(right==0){
            return 1+left;
        }
        return 1+Math.min(left,right);
    }

}