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| // @Title: 最长同值路径 (Longest Univalue Path)
// @Author: 15816537946@163.com
// @Date: 2019-11-25 09:30:33
// @Runtime: 84 ms
// @Memory: 6.7 MB
/**
* Definition for a binary tree node.
* type TreeNode struct {
* Val int
* Left *TreeNode
* Right *TreeNode
* }
*/
func longestUnivaluePath(root *TreeNode) int {
var path int
var helper func(*TreeNode) int
helper = func(node *TreeNode) int {
if node == nil {
return 0
}
left := helper(node.Left)
right := helper(node.Right)
var leftPath, rightPath int
if node.Left != nil && node.Left.Val == node.Val {
leftPath = left + 1
}
if node.Right != nil && node.Right.Val == node.Val {
rightPath = right + 1
}
path = max(path, leftPath+rightPath)
return max(leftPath, rightPath)
}
helper(root)
return path
}
func max(a, b int) int {
if a > b {
return a
}
return b
}
|