Merge branch 'main' of github.com:doocs/leetcode into main

Author: yanglbme

solution/0100-0199/0103.Binary Tree Zigzag Level Order Traversal/Solution.cpp

@@ -0,0 +1,33 @@
+/**
+ * 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>> zigzagLevelOrder(TreeNode* root) {
+        if (!root) return {};
+        vector<vector<int>> res;
+        queue<TreeNode*> q{{root}};
+        bool leftToRight = true;
+        while (!q.empty()) {
+            int size = q.size();
+            vector<int> oneLevel(size);
+            for (int i = 0; i < size; ++i) {
+                TreeNode* t = q.front();
+                q.pop();
+                int idx = leftToRight ? i : (size - 1 - i);
+                oneLevel[idx] = t->val;
+                if (t->left) q.push(t->left);
+                if (t->right) q.push(t->right);
+            }
+            leftToRight = !leftToRight;
+            res.push_back(oneLevel);
+        }
+        return res;
+    }
+};