Binary Tree Level Order Traversal LeetCode solution in C++

1
class Solution {
2
 public:
3
  vector<vector<int>> levelOrder(TreeNode *root) {
4
    queue<TreeNode *> q;
5
    vector<vector<int>> result;
6
    if (root == NULL) return result;
7
    q.push(root);
8
    q.push(NULL);
9
    vector<int> temp;
10
    while (!q.empty()) {
11
      TreeNode *top = q.front();
12
      q.pop();
13
      if (top == NULL) {
14
        result.push_back(temp);
15
        temp.clear();
16
        if (!q.empty()) {
17
          q.push(NULL);
18
          continue;
19
        }
20
        return result;
21
      } else
22
        temp.push_back(top->val);
23

24
      if (top->left) q.push(top->left);
25

26
      if (top->right) q.push(top->right);
27
    }
28

29
    return result;
30
  }
31
};