35 lines
704 B
Go
35 lines
704 B
Go
// Package q1372 implements a solution for https://leetcode.com/problems/longest-zigzag-path-in-a-binary-tree/
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package q1372
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type TreeNode struct {
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Val int
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Left *TreeNode
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Right *TreeNode
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}
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func zigZagLen(node *TreeNode, isLeft bool, curLen int) int {
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if node == nil {
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return 0
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}
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var l, r int
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if isLeft {
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l = zigZagLen(node.Left, true, 1)
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r = zigZagLen(node.Right, false, curLen+1)
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} else {
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l = zigZagLen(node.Left, true, curLen+1)
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r = zigZagLen(node.Right, false, 1)
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}
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return max(curLen, l, r)
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}
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func longestZigZag(root *TreeNode) int {
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if root == nil {
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return 0
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}
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return max(
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zigZagLen(root.Left, true, 1),
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zigZagLen(root.Right, false, 1),
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)
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}
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var _ = longestZigZag
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