Binary Tree Maximum Path Sum，binarymaximum

Binary Tree Maximum Path Sum，binarymaximum
題目來自於LeetCodehttps://leetcode.com/problems/binary-tree-maximum-path-sum/
Binary Tree Maximum Path Sum Total Accepted: 37936 Total Submissions: 178064My SubmissionsQuestion Solution 

Given a binary tree, find the maximum path sum.

The path may start and end at any node in the tree.

For example:
Given the below binary tree,

       1      / \     2   3

Return 6.

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/** * 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 maxroute(TreeNode* root)    {        if(root==NULL)        return  0;        int left=maxroute(root->left);        int right=maxroute(root->right);        int tmp=left>right?left:right;       res=(root->val)>res?root->val:res;       if(tmp>left+right&&root->val+tmp>res)res=root->val+tmp;else if(root->val+left+right>res)             res=root->val+left+right;return (tmp>0?root->val+tmp:root->val);    }    int maxPathSum(TreeNode* root) {                if (root==NULL)         return 0;        if(root->left==NULL&&root->right==NULL)          return root->val;          res=root->val;          int cc= maxroute( root);        return res;    }     int res;};