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(NULL), right(NULL) {
    }
};
*/
class Solution {
public:
    vector<vector<int> > Print(TreeNode* head) {
        if(head==nullptr) return {};
        queue<TreeNode *> q;

        vector<vector<int>> res;
        vector<int> temp;
        q.push(head);
        int high=1;

        while(!q.empty()){
            int sz=q.size();
            for(int i=0;i<sz;i++){
                TreeNode* p=q.front();
                q.pop();
                temp.push_back(p->val);
                if(p->left)  q.push(p->left);
                if(p->right) q.push(p->right);
            }
            if(high%2==0) reverse(temp.begin(),temp.end());
            high++;
            res.push_back(temp);
            temp.clear();
        }

        return res;
    }

};