55 lines
985 B
Go
55 lines
985 B
Go
package q103
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import "slices"
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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 zigzagLevelOrder(root *TreeNode) [][]int {
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ret := [][]int{}
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if root == nil {
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return ret
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}
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dpth := 1
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buf := make([]int, 512)
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row := buf[:0]
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type qElem struct {
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depth int
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node *TreeNode
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}
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queue := make([]qElem, 0, 256)
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queue = append(queue, qElem{depth: 1, node: root})
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for ; len(queue) > 0; queue = queue[1:] {
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c := queue[0]
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if c.depth > dpth {
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if dpth%2 == 0 {
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slices.Reverse(row)
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}
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ret = append(ret, make([]int, len(row)))
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copy(ret[len(ret)-1], row)
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dpth = c.depth
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row = buf[:0]
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}
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row = append(row, c.node.Val)
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if c.node.Left != nil {
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queue = append(queue, qElem{depth: c.depth + 1, node: c.node.Left})
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}
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if c.node.Right != nil {
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queue = append(queue, qElem{depth: c.depth + 1, node: c.node.Right})
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}
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}
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if dpth%2 == 0 {
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slices.Reverse(row)
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}
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ret = append(ret, row)
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return ret
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}
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var _ = zigzagLevelOrder
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