LeetCode 102. Binary Tree Level Order Traversal

LeetCode 102. Binary Tree Level Order Traversal

Solution1:
参考自《剑指offer》上的资料：https://blog.youkuaiyun.com/allenlzcoder/article/details/79785180

/**
 * Definition for a binary tree node.
 * struct TreeNode {
 *     int val;
 *     TreeNode *left;
 *     TreeNode *right;
 *     TreeNode(int x) : val(x), left(NULL), right(NULL) {}
 * };
 */
class Solution {
public:
    vector<vector<int>> levelOrder(TreeNode* root) {
        vector<vector<int> > res;
        if (!root) return res;
        vector<int> temp;
        queue<TreeNode* > my_que; //队列用来暂时存储二叉树节点
        my_que.push(root);
        int cur = 1, next = 0;
        while (!my_que.empty()) {
            temp.push_back(my_que.front()->val);
            cur--;
            if (my_que.front()->left) {
                my_que.push(my_que.front()->left);
                next++;
            }
            if (my_que.front()->right) {
                my_que.push(my_que.front()->right);
                next++;
            }
            my_que.pop();
            if (cur == 0) {
                res.push_back(temp);
                temp.clear();
                cur = next;
                next = 0;
            }
        }
        return res;
    }
};