题解 | #二叉树深度#

非递归求解·

/**
public class TreeNode {
    int val = 0;
    TreeNode left = null;
    TreeNode right = null;

    public TreeNode(int val) {
        this.val = val;

    }

}
*/
import java.util.*;
public class Solution {
    public int TreeDepth(TreeNode root) {
        LinkedList <TreeNode> list = new LinkedList<TreeNode>();
        if(root == null){
        return 0;
        }
        int level = 0;
        list.add(root);
        while(!list.isEmpty()){
          //记录当前层的节点个数
            int curSize = list.size();
            while(curSize>0){
                TreeNode curNode = list.poll();
                if(curNode.left!=null){
                    list.add(curNode.left);
                }
                if(curNode.right!=null){
                    list.add(curNode.right);
                }
                curSize--;
            }
            level++;
        }
        return level;
    }
}