LeetCode:Diameter of Binary Tree

543. Diameter of Binary Tree

Given a binary tree, you need to compute the length of the diameter of the tree. The diameter of a binary tree is the length of the longest path between any two nodes in a tree. This path may or may not pass through the root.

Example:
Given a binary tree 

          1
         / \
        2   3
       / \     
      4   5

 

Return 3, which is the length of the path [4,2,1,3] or [5,2,1,3].

思路：这个题目的思路还是比较直接的，记录下每个节点的深度以及以当前节点为连接点的最大长度，遍历一遍取最大值即可。

 1 struct res{
 2     int d;
 3     int m;
 4     res(int depth, int max) :d(depth), m(max){}
 5 };
 6 struct res diaOfBinaryTree(TreeNode* t,int* dia)
 7 {
 8     if (t == NULL)
 9     {
10         struct res res(0, 0);
11         return res;
12     }
13     struct res l = diaOfBinaryTree(t->left,dia);
14     struct res r = diaOfBinaryTree(t->right,dia);
15     struct res res(max(l.d,r.d)+1,l.d+r.d+1);
16     *dia = max(*dia, l.d + r.d + 1);
17     return res;
18 }
19 int diameterOfBinaryTree(TreeNode* root) {
20     int dia = 0;
21     diaOfBinaryTree(root, &dia);
22     return dia;
23 }

 

 

如果你有任何疑问或新的想法，欢迎在下方评论。

posted @ 2017-03-21 12:44  陆小风不写代码  阅读(279)  评论(0)  编辑  收藏  举报