Add Solution for 124 in cpp and go

Author: KongJHong

solution/0124.Binary Tree Maximum Path Sum/Solution.cpp

@@ -0,0 +1,27 @@
+/**
+ * Definition for a binary tree node.
+ * struct TreeNode {
+ *     int val;
+ *     TreeNode *left;
+ *     TreeNode *right;
+ *     TreeNode(int x) : val(x), left(NULL), right(NULL) {}
+ * };
+ */
+class Solution {
+public:
+    int maxPathSum(TreeNode* root) {
+        int maxInt = INT_MIN;
+        dfs(root,maxInt);
+        return maxInt;
+    }
+    
+    
+    int dfs(TreeNode *root,int &maxInt){
+        if(root == nullptr)return 0;
+        
+        int left = max(dfs(root->left,maxInt),0);
+        int right = max(dfs(root->right,maxInt),0);
+        maxInt = max(maxInt,left + right + root->val);
+        return max(left,right) + root->val;
+    }  
+};

solution/0124.Binary Tree Maximum Path Sum/Solution.go

@@ -0,0 +1,37 @@
+/**
+ * Definition for a binary tree node.
+ * type TreeNode struct {
+ *     Val int
+ *     Left *TreeNode
+ *     Right *TreeNode
+ * }
+ */
+
+ import(
+    "math"
+)
+
+func maxPathSum(root *TreeNode) int {
+    maxInt := math.MinInt32
+    dfs(root,&maxInt)
+    return maxInt
+}
+
+func dfs(root *TreeNode,maxInt *int) int {
+    if root == nil{
+        return 0
+    }
+    
+    left := max(0,dfs(root.Left,maxInt))
+    right := max(0,dfs(root.Right,maxInt))
+    *maxInt = max(*maxInt,root.Val + left + right)
+    return max(left,right) + root.Val
+}
+
+
+func max(a,b int) int{
+    if a > b{
+        return a
+    }
+    return b
+}