feat:add Solution.cpp for 0103. Binary Tree Zigzag Level Order Traversal

Author: Stackingrule

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

@@ -0,0 +1,23 @@
+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;
+    }
+};