剑指Offer-22-从上往下打印二叉树

题目描述

从上往下打印出二叉树的每个节点，同层节点从左至右打印。

Code

//思路二叉树的层序遍历
/*
struct TreeNode {
	int val;
	struct TreeNode *left;
	struct TreeNode *right;
	TreeNode(int x) :
			val(x), left(NULL), right(NULL) {
	}
};*/
class Solution {
public:
    vector<int> PrintFromTopToBottom(TreeNode* root) {
        vector<int> res;//结果集
        if(!root)
            return res;
        TreeNode* temp = root;
        queue<TreeNode*> q;
        
        q.push(temp);
        while(!q.empty()){
            temp = q.front();
            res.push_back(temp->val);
            q.pop();
            if(temp->left!=NULL)
                q.push(temp->left);
            if(temp->right!=NULL)
                q.push(temp->right);
        }
        return res;
    }
};