95 312

Author: LuYanFCP

README.md

@@ -15,6 +15,7 @@ Leetcode刷题记录
 + No.126 [cpp](cpp/126.cpp) [python](python/126.py)
 + No.543 [cpp](cpp/543.cpp) [python](python/543.py)
 + No.785 [cpp-dfs](cpp/785.cpp) [cpp-bfs](cpp/785-bfs.cpp)  **二分图染色问题**
++ No.95 [cpp](cpp/95.cpp)
 
 ### 并查集
 
@@ -72,6 +73,7 @@ Leetcode刷题记录
 + No.126 [cpp](cpp/126.cpp) [python](python/126.py)
 + No.1014 [cpp](cpp/1014.cpp) [python](python/1014.py) easy
 + No.174  [cpp](cpp/174.cpp) [python](python/174.py) [java](java/Problem174.java)
++ No.312 [cpp](cpp/312.cpp)
 
 ### 状态机DP
 

cpp/312.cpp

@@ -0,0 +1,22 @@
+#include <bits/stdc++.h>
+using namespace std;
+
+class Solution {
+public:
+    int maxCoins(vector<int>& nums) {
+        int n = nums.size();
+        vector<int> vec(n+2, 1);  // 让开最后一个和第一个放1
+        for (int i = 1; i <= n; ++i) vec[i] = nums[i-1];
+
+        vector<vector<int>> dp(n+2, vector<int>(n+2, 0));
+        for (int i = n+1; i >= 0; --i) {
+            for (int j = i; j <= n+1; ++j) {
+                if (j - i < 2) dp[i][j] = 0;
+                for (int k = i+1; k <= j-1; ++k) {
+                    dp[i][j] = max(dp[i][j], dp[i][k] + dp[k][j] + vec[i] * vec[k] * vec[j]);
+                }
+            }
+        }
+        return dp[0][n+1];
+    }
+};

cpp/95.cpp

@@ -0,0 +1,47 @@
+#include <bits/stdc++.h>
+using namespace std;
+/**
+ * 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) {}
+ * };
+ */
+
+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<TreeNode*> generateTrees(int n) {
+        if(n == 0) return {};
+        return generateTrees(1,n);
+    }
+    
+    vector<TreeNode*> generateTrees(int begin, int end) {
+        
+        vector<TreeNode*> ans;
+        if(begin > end) return {nullptr}; // 返回， 边界条件
+        // 递归代码
+        for(int i=begin; i<=end; i++) {  // 将任意作为中心
+            for(auto& l : generateTrees(begin, i-1)) {  // 前半部分
+                for(auto& r : generateTrees(i+1, end)) { // 后半部分
+                    TreeNode* root = new TreeNode(i,l,r);
+                    ans.push_back(root);
+                }
+            }            
+        }
+        return ans;
+    }  
+};