0958.cpp (479B)
1 class Solution { 2 public: 3 bool isCompleteTree(TreeNode *root) { 4 queue<TreeNode *> q; 5 int had_empty = 0; 6 q.push(root); 7 while (!q.empty()) { 8 TreeNode *root = q.front(); 9 q.pop(); 10 if (!root) { 11 had_empty = 1; 12 continue; 13 } 14 if (had_empty) return false; 15 q.push(root->left); 16 q.push(root->right); 17 } 18 return true; 19 } 20 };