题解 | 按之字形顺序打印二叉树

/**
 * struct TreeNode {
 *	int val;
 *	struct TreeNode *left;
 *	struct TreeNode *right;
 *	TreeNode(int x) : val(x), left(nullptr), right(nullptr) {}
 * };
 */
class Solution {
public:
    /**
     * 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 pRoot TreeNode类 
     * @return int整型vector<vector<>>
     */
    vector<vector<int> > Print(TreeNode* pRoot) {
        // write code here
        vector<vector<int>> res;

        if(pRoot==nullptr) return {};

        queue<TreeNode*> q;
        q.push(pRoot);
        int dep=1;

        while(!q.empty())
        {
            int l=q.size();
            vector<int> cur;
            dep++;

            for(int i=0;i<l;i++)
            {
                TreeNode* node = q.front();
                q.pop();
                cur.push_back(node->val);

                if(node->left) q.push(node->left);
                if(node->right) q.push(node->right);
            }
            if(dep%2==1) reverse(cur.begin(),cur.end());
            res.push_back(cur);
        }
        return res;
    }
};