116 lines
2.7 KiB
Go
116 lines
2.7 KiB
Go
// File: array_deque.go
|
|
// Created Time: 2023-03-13
|
|
// Author: Reanon (793584285@qq.com)
|
|
|
|
package chapter_stack_and_queue
|
|
|
|
import "fmt"
|
|
|
|
/* Double-ended queue class based on circular array */
|
|
type arrayDeque struct {
|
|
nums []int // Array used to store elements of the double-ended queue
|
|
front int // Front pointer, pointing to the front element
|
|
queSize int // Length of the double-ended queue
|
|
queCapacity int // Queue capacity (i.e., maximum number of elements it can hold)
|
|
}
|
|
|
|
/* Initialize queue */
|
|
func newArrayDeque(queCapacity int) *arrayDeque {
|
|
return &arrayDeque{
|
|
nums: make([]int, queCapacity),
|
|
queCapacity: queCapacity,
|
|
front: 0,
|
|
queSize: 0,
|
|
}
|
|
}
|
|
|
|
/* Get the length of the double-ended queue */
|
|
func (q *arrayDeque) size() int {
|
|
return q.queSize
|
|
}
|
|
|
|
/* Determine if the double-ended queue is empty */
|
|
func (q *arrayDeque) isEmpty() bool {
|
|
return q.queSize == 0
|
|
}
|
|
|
|
/* Calculate circular array index */
|
|
func (q *arrayDeque) index(i int) int {
|
|
// Implement circular array by modulo operation
|
|
// When i exceeds the tail of the array, return to the head
|
|
// When i exceeds the head of the array, return to the tail
|
|
return (i + q.queCapacity) % q.queCapacity
|
|
}
|
|
|
|
/* Front enqueue */
|
|
func (q *arrayDeque) pushFirst(num int) {
|
|
if q.queSize == q.queCapacity {
|
|
fmt.Println("Double-ended queue is full")
|
|
return
|
|
}
|
|
// Move the front pointer one position to the left
|
|
// Implement front crossing the head of the array to return to the tail by modulo operation
|
|
q.front = q.index(q.front - 1)
|
|
// Add num to the front
|
|
q.nums[q.front] = num
|
|
q.queSize++
|
|
}
|
|
|
|
/* Rear enqueue */
|
|
func (q *arrayDeque) pushLast(num int) {
|
|
if q.queSize == q.queCapacity {
|
|
fmt.Println("Double-ended queue is full")
|
|
return
|
|
}
|
|
// Calculate rear pointer, pointing to rear index + 1
|
|
rear := q.index(q.front + q.queSize)
|
|
// Add num to the rear
|
|
q.nums[rear] = num
|
|
q.queSize++
|
|
}
|
|
|
|
/* Front dequeue */
|
|
func (q *arrayDeque) popFirst() any {
|
|
num := q.peekFirst()
|
|
// Move front pointer one position backward
|
|
q.front = q.index(q.front + 1)
|
|
q.queSize--
|
|
return num
|
|
}
|
|
|
|
/* Rear dequeue */
|
|
func (q *arrayDeque) popLast() any {
|
|
num := q.peekLast()
|
|
q.queSize--
|
|
return num
|
|
}
|
|
|
|
/* Access front element */
|
|
func (q *arrayDeque) peekFirst() any {
|
|
if q.isEmpty() {
|
|
return nil
|
|
}
|
|
return q.nums[q.front]
|
|
}
|
|
|
|
/* Access rear element */
|
|
func (q *arrayDeque) peekLast() any {
|
|
if q.isEmpty() {
|
|
return nil
|
|
}
|
|
// Calculate rear element index
|
|
last := q.index(q.front + q.queSize - 1)
|
|
return q.nums[last]
|
|
}
|
|
|
|
/* Get Slice for printing */
|
|
func (q *arrayDeque) toSlice() []int {
|
|
// Only convert elements within valid length range
|
|
res := make([]int, q.queSize)
|
|
for i, j := 0, q.front; i < q.queSize; i++ {
|
|
res[i] = q.nums[q.index(j)]
|
|
j++
|
|
}
|
|
return res
|
|
}
|