Merge pull request #109 from divya1509/master

Create Binary Tree Maximum Path Sum

Author: SarthakKeshari

LeetCode/Binary Tree Maximum Path Sum

@@ -0,0 +1,46 @@
+// link- https://leetcode.com/problems/binary-tree-maximum-path-sum/
+
+// Approach:
+// Since a binary tree can have max 2 children so the path with max sum can either include both the children or one 
+// depending upon the max value that can be generated.
+// The same logic has been implemented in the following code which stores the final answer in the variable max 
+
+
+/**
+ * Definition for a binary tree node.
+ * public class TreeNode {
+ *     int val;
+ *     TreeNode left;
+ *     TreeNode right;
+ *     TreeNode() {}
+ *     TreeNode(int val) { this.val = val; }
+ *     TreeNode(int val, TreeNode left, TreeNode right) {
+ *         this.val = val;
+ *         this.left = left;
+ *         this.right = right;
+ *     }
+ * }
+ */
+class Solution {
+    int max = -1001;
+    
+    private int solve(TreeNode root) {
+        if(root == null) return 0;
+        
+        int ans_left = 0, ans_right = 0;
+        if(root.left != null) ans_left = Math.max(solve(root.left), 0);
+        if(root.right != null) ans_right = Math.max(solve(root.right), 0);
+        
+        int temp = root.val + Math.max(ans_left, ans_right);
+        max = Math.max(temp, max);
+        max = Math.max(root.val + ans_left + ans_right, max);
+        return temp;
+        
+    }
+    
+    public int maxPathSum(TreeNode root) {
+        max = -1001;
+        solve(root);
+        return max;
+    }
+}