0508 solved.

liuyubobobo · liuyubobobo · commit c376e8e54064 · 2022-06-18T09:41:48.000-07:00
diff --git a/0501-1000/0508-Most-Frequent-Subtree-Sum/cpp-0508/CMakeLists.txt b/0501-1000/0508-Most-Frequent-Subtree-Sum/cpp-0508/CMakeLists.txt
@@ -0,0 +1,6 @@
+cmake_minimum_required(VERSION 3.22)
+project(cpp_0508)
+
+set(CMAKE_CXX_STANDARD 14)
+
+add_executable(cpp_0508 main.cpp)
diff --git a/0501-1000/0508-Most-Frequent-Subtree-Sum/cpp-0508/main.cpp b/0501-1000/0508-Most-Frequent-Subtree-Sum/cpp-0508/main.cpp
@@ -0,0 +1,58 @@
+/// Source : https://leetcode.com/problems/most-frequent-subtree-sum/
+/// Author : liuyubobobo
+/// Time   : 2022-06-18
+
+#include <iostream>
+#include <vector>
+#include <map>
+
+using namespace std;
+
+
+/// DFS
+/// Time Compelxity: O(n)
+/// Space Complexity: O(n)
+
+/// Definition for a binary tree node.
+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 {
+public:
+    vector<int> findFrequentTreeSum(TreeNode* root) {
+
+        map<int, int> f;
+        dfs(root, f);
+
+        vector<int> res;
+        int max_f = 0;
+        for(const pair<int, int>& p: f)
+            if(p.second > max_f) res = {p.first}, max_f = p.second;
+            else if(p.second == max_f) res.push_back(p.first);
+        return res;
+    }
+
+private:
+    int dfs(TreeNode* node, map<int, int>& f){
+
+        if(!node) return 0;
+
+        int res = node->val;
+        res += dfs(node->left, f);
+        res += dfs(node->right, f);
+        f[res] ++;
+        return res;
+    }
+};
+
+
+int main() {
+
+    return 0;
+}
diff --git a/readme.md b/readme.md
@@ -537,7 +537,7 @@ email: [liuyubobobo@gmail.com](mailto:liuyubobobo@gmail.com)
 | 505 | [The Maze II](https://leetcode.com/problems/the-maze-ii/) | [solution](https://leetcode.com/problems/the-maze-ii/solution/) | [C++](0501-1000/0505-The-Maze-II/cpp-0505/) | | |
 | 506 | [Relative Ranks](https://leetcode.com/problems/relative-ranks/) | [无] | [C++](0501-1000/0506-Relative-Ranks/cpp-0506/) | | |
 | 507 | [Perfect Number](https://leetcode.com/problems/perfect-number/) | [solution](https://leetcode.com/problems/perfect-number/solution/) | [C++](0501-1000/0507-Perfect-Number/cpp-0507/) | | |
-| | | | | | |
+| 508 | [Most Frequent Subtree Sum](https://leetcode.com/problems/most-frequent-subtree-sum/) | [无] | [C++](0501-1000/0508-Most-Frequent-Subtree-Sum/cpp-0508/) | | |
 | 509 | [Fibonacci Number](https://leetcode.com/problems/fibonacci-number/) | [无] | [C++](0501-1000/0509-Fibonacci-Number/cpp-0509/) | | |
 | | | | | | |
 | 511 | Database Problem: [Link](https://github.com/liuyubobobo/Play-Leetcode-Database/) | - | - | - | - |
