hello-algo/codes/rust/chapter_stack_and_queue/array_queue.rs
Yudong Jin f68bbb0d59
Update the book based on the revised second edition (#1014)
* Revised the book

* Update the book with the second revised edition

* Revise base on the manuscript of the first edition
2023-12-28 18:06:09 +08:00

125 lines
3.1 KiB
Rust

/*
* File: array_queue.rs
* Created Time: 2023-02-06
* Author: WSL0809 (wslzzy@outlook.com)
*/
/* 基于环形数组实现的队列 */
struct ArrayQueue {
nums: Vec<i32>, // 用于存储队列元素的数组
front: i32, // 队首指针,指向队首元素
que_size: i32, // 队列长度
que_capacity: i32, // 队列容量
}
impl ArrayQueue {
/* 构造方法 */
fn new(capacity: i32) -> ArrayQueue {
ArrayQueue {
nums: vec![0; capacity as usize],
front: 0,
que_size: 0,
que_capacity: capacity,
}
}
/* 获取队列的容量 */
fn capacity(&self) -> i32 {
self.que_capacity
}
/* 获取队列的长度 */
fn size(&self) -> i32 {
self.que_size
}
/* 判断队列是否为空 */
fn is_empty(&self) -> bool {
self.que_size == 0
}
/* 入队 */
fn push(&mut self, num: i32) {
if self.que_size == self.capacity() {
println!("队列已满");
return;
}
// 计算队尾指针,指向队尾索引 + 1
// 通过取余操作实现 rear 越过数组尾部后回到头部
let rear = (self.front + self.que_size) % self.que_capacity;
// 将 num 添加至队尾
self.nums[rear as usize] = num;
self.que_size += 1;
}
/* 出队 */
fn pop(&mut self) -> i32 {
let num = self.peek();
// 队首指针向后移动一位,若越过尾部,则返回到数组头部
self.front = (self.front + 1) % self.que_capacity;
self.que_size -= 1;
num
}
/* 访问队首元素 */
fn peek(&self) -> i32 {
if self.is_empty() {
panic!("index out of bounds");
}
self.nums[self.front as usize]
}
/* 返回数组 */
fn to_vector(&self) -> Vec<i32> {
let cap = self.que_capacity;
let mut j = self.front;
let mut arr = vec![0; self.que_size as usize];
for i in 0..self.que_size {
arr[i as usize] = self.nums[(j % cap) as usize];
j += 1;
}
arr
}
}
/* Driver Code */
fn main() {
/* 初始化队列 */
let capacity = 10;
let mut queue = ArrayQueue::new(capacity);
/* 元素入队 */
queue.push(1);
queue.push(3);
queue.push(2);
queue.push(5);
queue.push(4);
println!("队列 queue = {:?}", queue.to_vector());
/* 访问队首元素 */
let peek = queue.peek();
println!("队首元素 peek = {}", peek);
/* 元素出队 */
let pop = queue.pop();
println!(
"出队元素 pop = {:?},出队后 queue = {:?}",
pop,
queue.to_vector()
);
/* 获取队列的长度 */
let size = queue.size();
println!("队列长度 size = {}", size);
/* 判断队列是否为空 */
let is_empty = queue.is_empty();
println!("队列是否为空 = {}", is_empty);
/* 测试环形数组 */
for i in 0..10 {
queue.push(i);
queue.pop();
println!("{:?} 轮入队 + 出队后 queue = {:?}", i, queue.to_vector());
}
}