題目
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.
解題思路
遍歷二叉樹，求每個(gè)節(jié)點(diǎn)的左子樹深度和右子樹深度和的最大值。
代碼
/**
* Definition for a binary tree node.
* type TreeNode struct {
* Val int
* Left *TreeNode
* Right *TreeNode
* }
*/
var maxDiameter int
func MaxDeepth(t *TreeNode) (deepth int) {
if nil == t {
return 0
}
left := MaxDeepth(t.Left)
right := MaxDeepth(t.Right)
maxDiameter = int(math.Max(float64(maxDiameter), float64(left + right)))
return int(math.Max(float64(left), float64(right))) + 1
}
func diameterOfBinaryTree(root *TreeNode) int {
maxDiameter = 0
if nil == root {
return 0
}
MaxDeepth(root)
return maxDiameter
}
