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].
Note: The length of path between two nodes is represented by the number of edges between them.
题目大意
给出一颗二叉树,求叶节点之间的最大距离。
思路
求叶节点的最大距离,可能这个最大的距离并不通过根节点,最大距离为左子树深度与右子树深度之和再加一。所以只需求每个节点的左右子树最大深度即可,边求边得出最大值。
代码
/**
* 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 ans;
int diameterOfBinaryTree(TreeNode* root) {
ans=1;
depth(root);
return ans-1;
}
int depth(TreeNode* root)
{
if(!root)
return 0;
int L=depth(root->left);
int R=depth(root->right);
ans=max(ans,L+R+1);
return max(L,R)+1;
}
};