Create Binary Tree Maximum Path Sum.cpp

Author: daizhenyang

Binary Tree Maximum Path Sum.cpp

@@ -0,0 +1,40 @@
+/**
+ * Definition for binary tree
+ * struct TreeNode {
+ *     int val;
+ *     TreeNode *left;
+ *     TreeNode *right;
+ *     TreeNode(int x) : val(x), left(NULL), right(NULL) {}
+ * };
+ */
+class Solution {
+public:
+    int ans;
+    int dfs(TreeNode *r)
+    {
+        int mx=0,x=r->val;
+        if (r->left)
+        {
+            int z=dfs(r->left);
+            mx=max(mx,z);
+            x+=z;
+        }
+        if (r->right)
+        {
+            int z=dfs(r->right);
+            mx=max(mx,z);
+            x+=z;
+        }
+        ans=max(ans,r->val+mx);
+        ans=max(ans,x);
+        return r->val+mx;
+    }
+    int maxPathSum(TreeNode *root) {
+        // Start typing your C/C++ solution below
+        // DO NOT write int main() function
+        if (!root)return 0;
+        ans=root->val;
+        dfs(root);
+        return ans;
+    }
+};