leetcode

Solution to some Leetcode problems written in C++

git clone git://git.dimitrijedobrota.com/leetcode.git

0103.cpp (1696B)

0 class Solution { 1 public: 2 vector<vector<int>> zigzagLevelOrder(TreeNode *root) { 3 if (!root) return {}; 4 5 vector<vector<int>> res; 6 queue<TreeNode *> q; 7 bool right = true; 8 9 q.push(root); 10 for (int lvl = 0; !q.empty(); lvl++) { 11 res.push_back(vector<int>()); 12 for (int t = q.size(); t > 0; t--) { 13 TreeNode *root = q.front(); 14 q.pop(); 15 res[lvl].push_back(root->val); 16 17 if (root->left) q.push(root->left); 18 if (root->right) q.push(root->right); 19 } 20 if (!right) reverse(res[lvl].begin(), res[lvl].end()); 21 right = !right; 22 } 23 return res; 24 } 25 26 vector<vector<int>> zigzagLevelOrder(TreeNode *root) { 27 if (!root) return {}; 28 29 vector<vector<int>> res; 30 deque<TreeNode *> d; 31 bool right = true; 32 33 d.push_front(root); 34 for (int lvl = 0; !d.empty(); lvl++, right = !right) { 35 res.push_back(vector<int>()); 36 for (int t = d.size(); t > 0; t--) { 37 TreeNode *root; 38 if (right) { 39 root = d.front(); 40 d.pop_front(); 41 if (root->left) d.push_back(root->left); 42 if (root->right) d.push_back(root->right); 43 } else { 44 root = d.back(); 45 d.pop_back(); 46 if (root->right) d.push_front(root->right); 47 if (root->left) d.push_front(root->left); 48 } 49 res[lvl].push_back(root->val); 50 } 51 } 52 return res; 53 } 54 };