add: 220713

cpp/2207/220713.cpp

@@ -0,0 +1,37 @@
+#include <vector>
+#include <queue>
+#include <utility>
+
+struct TreeNode {
+	int val;
+	TreeNode* left;
+	TreeNode* right;
+	explicit TreeNode(int x, TreeNode* left = nullptr, TreeNode* right = nullptr) : val(x), left(left), right(right) {}
+};
+
+
+class Solution {
+public:
+	std::vector<std::vector<int>> levelOrder(TreeNode* root) {
+		if (!root)
+			return {};
+		std::vector<std::vector<int>> ret {{}};
+		std::queue<std::pair<const TreeNode*, int>> q;
+		q.push({root, 0});
+		int cl = 0;
+		while (!q.empty()) {
+			const auto [v, l] = q.front();
+			q.pop();
+			if (l > cl) {
+				++cl;
+				ret.emplace_back();
+			}
+			ret.back().push_back(v->val);
+			if (v->left)
+				q.push({v->left, 1 + l});
+			if (v->right)
+				q.push({v->right, 1 + l});
+		}
+		return ret;
+	}
+};