leetcode -- Binary Tree Maximum Path Sum

过去只是人生经历，并不是人生负担

[问题描述]

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.

[解题思路]

类似于最大连续子序列

 1 class Solution {
 2 public:
 3     int maxPathSum(TreeNode *root) {
 4         max_sum = root->val;
 5         tt(root);
 6         return max_sum;
 7     }
 8     int tt(TreeNode *root){
 9         if (root == NULL)
10             return 0;
11         int sum = root->val;
12         int l = tt(root->left);
13         int r = tt(root->right);
14         sum += max(l, 0);
15         sum += max(r, 0);
16         max_sum = max(max_sum, sum);
17         return max(l, r) > 0?(root->val + max(l, r)):(root->val);
18     }
19 private:
20     int max_sum;
21 };

 

posted on 2014-10-07 11:18  雨歌_sky  阅读(141)  评论(0)  编辑  收藏  举报

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