add: 230315

cpp/2303/230315.cpp

@@ -0,0 +1,44 @@
+#include <queue>
+#include <utility>
+#include <iostream>
+
+struct TreeNode {
+	int val;
+	TreeNode* left;
+	TreeNode* right;
+
+	explicit TreeNode(int x, TreeNode* left = nullptr, TreeNode* right = nullptr) : val(x), left(left), right(right) {}
+};
+
+/**
+ * 958. Check Completeness of a Binary Tree
+ *
+ * Given the root of a binary tree, determine if it is a complete binary tree.
+ * In a complete binary tree, every level, except possibly the last, is completely filled, and all nodes in the last level are as far left as possible. It can have between 1 and 2h nodes inclusive at the last level h.
+ */
+
+class Solution {
+public:
+	static bool isCompleteTree(const TreeNode* r) {
+		std::queue<std::pair<int, const TreeNode*>> q;
+		q.emplace(1, r);
+		for (int c = 1; !q.empty(); ++c) {
+			const auto [v, p] = q.front();
+			q.pop();
+			if (v != c)
+				return false;
+			if (p->left) {
+				q.emplace(v << 1, p->left);
+				if (p->right)
+					q.emplace(v << 1 | 1, p->right);
+			} else if (p->right) return false;
+		}
+		return true;
+	}
+};
+
+int main() {
+	auto* t = new TreeNode(1, new TreeNode(2, new TreeNode(4), new TreeNode(5)), new TreeNode(3, nullptr, new TreeNode(6)));
+	std::cout << Solution::isCompleteTree(t);
+	return 0;
+}

cpp/2303/CMakeLists.txt

@@ -3,4 +3,4 @@ PROJECT(2303)
 
 SET(CMAKE_CXX_STANDARD 23)
 
-ADD_EXECUTABLE(2303 230314.cpp)
+ADD_EXECUTABLE(2303 230315.cpp)