Initial commit

Medium/binary-tree-level-order-traversal/solution.cpp

@@ -0,0 +1,35 @@
+#include <vector>
+
+struct TreeNode {
+    int val;
+    TreeNode *left;
+    TreeNode *right;
+    TreeNode() : val(0), left(nullptr), right(nullptr) {}
+    TreeNode(int x) : val(x), left(nullptr), right(nullptr) {}
+    TreeNode(int x, TreeNode *left, TreeNode *right)
+        : val(x), left(left), right(right) {}
+};
+
+class Solution {
+  private:
+    void levelOrder(std::vector<std::vector<int>> &levels, TreeNode *root,
+                    int index) {
+        if (root == nullptr) {
+            return;
+        } else if (levels.size() == index) {
+            levels.push_back(std::vector<int>{});
+        }
+
+        levels[index].push_back(root->val);
+        levelOrder(levels, root->left, index + 1);
+        levelOrder(levels, root->right, index + 1);
+    }
+
+  public:
+    std::vector<std::vector<int>> levelOrder(TreeNode *root) {
+        std::vector<std::vector<int>> levels;
+        levelOrder(levels, root, 0);
+
+        return levels;
+    }
+};