Go for Binary Tree MAximum Path Sum

Author: falldio

Trees.md

@@ -817,6 +817,39 @@ private:
 };
 ```
 
+```go
+/**
+ * Definition for a binary tree node.
+ * type TreeNode struct {
+ *     Val int
+ *     Left *TreeNode
+ *     Right *TreeNode
+ * }
+ */
+func maxPathSum(root *TreeNode) int {
+    ans := -1 << 63
+    maxPath(root, &ans)
+    return ans
+}
+
+func maxPath(root *TreeNode, ans *int) int {
+    if root == nil {
+        return 0
+    }
+    leftPathSum := maxPath(root.Left, ans)
+    rightPathSum := maxPath(root.Right, ans)
+    *ans = max(*ans, leftPathSum + rightPathSum + root.Val)
+    return max(max(leftPathSum+root.Val, rightPathSum+root.Val), 0)
+}
+
+func max(a int, b int) int {
+    if (a >= b) {
+        return a
+    }
+    return b
+}
+```
+
 ## [Serialize and Deserialize Binary Tree](https://leetcode.com/problems/serialize-and-deserialize-binary-tree)
 
 A: