scratch/algos/queue.go (view raw)
| 1 | package algos |
| 2 | |
| 3 | type QNode[T any] struct { |
| 4 | v T |
| 5 | next *QNode[T] |
| 6 | } |
| 7 | |
| 8 | type Queue[T any] struct { |
| 9 | Len int |
| 10 | head *QNode[T] |
| 11 | tail *QNode[T] |
| 12 | } |
| 13 | |
| 14 | func (q *Queue[T]) Push(item T) { |
| 15 | node := &QNode[T]{v: item} |
| 16 | if q.Len == 0 { |
| 17 | q.head = node |
| 18 | q.tail = node |
| 19 | } else { |
| 20 | q.tail.next = node |
| 21 | q.tail = node |
| 22 | } |
| 23 | q.Len++ |
| 24 | } |
| 25 | |
| 26 | func (q *Queue[T]) Peek() T { |
| 27 | return q.head.v |
| 28 | } |
| 29 | |
| 30 | func (q *Queue[T]) Pop() (T, bool) { |
| 31 | if q.Len == 0 { |
| 32 | var t T |
| 33 | return t, false |
| 34 | } |
| 35 | |
| 36 | res := q.head.v |
| 37 | q.head = q.head.next |
| 38 | if q.head == nil { |
| 39 | q.tail = nil |
| 40 | } |
| 41 | q.Len-- |
| 42 | return res, true |
| 43 | } |