add: 230420

cpp/2304/230420.cpp

@@ -0,0 +1,53 @@
+#include <algorithm>
+#include <queue>
+#include <tuple>
+
+struct TreeNode {
+	int val;
+	TreeNode* left;
+	TreeNode* right;
+
+	explicit TreeNode(int x, TreeNode* left = nullptr, TreeNode* right = nullptr) : val(x), left(left), right(right) {}
+};
+
+/**
+ * 662. Maximum Width of Binary Tree
+ *
+ * Given the root of a binary tree, return the maximum width of the given tree.
+ * The maximum width of a tree is the maximum width among all levels.
+ * The width of one level is defined as the length between the end-nodes (the leftmost and rightmost non-null nodes), where the null nodes between the end-nodes that would be present in a complete binary tree extending down to that level are also counted into the length calculation.
+ * It is guaranteed that the answer will in the range of a 32-bit signed integer.
+ */
+
+class Solution {
+public:
+	static int widthOfBinaryTree(const TreeNode* root);
+};
+
+int Solution::widthOfBinaryTree(const TreeNode* root) {
+	std::queue<std::tuple<const TreeNode*, int, unsigned long long>> q;
+	q.emplace(root, 0, 1);
+	int curLevel = -1;
+	std::pair<unsigned long long, unsigned long long> ans = {0, 0};
+	unsigned long long ret = 1;
+	while (!q.empty()) {
+		auto [node, level, id] = q.front();
+		q.pop();
+		if (curLevel != level) {
+			curLevel = level;
+			ret = std::max(ans.second - ans.first + 1, ret);
+			ans = {id, id};
+		}
+		ans.first = std::min(id, ans.first);
+		ans.second = std::max(id, ans.second);
+		if (node->left)
+			q.emplace(node->left, 1 + level, id << 1);
+		if (node->right)
+			q.emplace(node->right, 1 + level, 1 | (id << 1));
+	}
+	return std::max(ret, ans.second - ans.first + 1);
+}
+
+int main() {
+	;
+}