Create main.cpp

Author: JawadSher

18 - Binary Search Tree Data Structure Problems/19 - Maximum Sum BST in Binary Tree/main.cpp

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+/**
+ * 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 nodeInfo{
+    public:
+        int mini;
+        int maxi;
+        bool isBST;
+        int size;
+        int sum;
+};
+class Solution {
+public:
+    nodeInfo getLargestBSTSize(TreeNode* root, int &ans){
+        if(root == NULL) return nodeInfo{INT_MAX, INT_MIN, true, 0, 0};
+
+        nodeInfo left = getLargestBSTSize(root -> left, ans);
+        nodeInfo right = getLargestBSTSize(root -> right, ans);
+
+        nodeInfo currentNode;
+        currentNode.size = left.size + right.size + 1;
+        currentNode.sum = left.sum + right.sum + root -> val;
+        currentNode.mini = min(root -> val, left.mini);
+        currentNode.maxi = max(root -> val, right.maxi);
+
+        if(left.isBST && right.isBST && (root -> val > left.maxi && root -> val < right.mini)){
+            currentNode.isBST = true;
+            ans = max(ans, currentNode.sum);
+        }else{
+            currentNode.isBST = false;
+        }
+        
+        return currentNode;
+    }
+
+    int maxSumBST(TreeNode* root) {
+        int max_sum = 0;
+        getLargestBSTSize(root, max_sum);
+        return max_sum;
+    }
+};