66 lines
1.5 KiB
Rust
66 lines
1.5 KiB
Rust
#[derive(Debug)]
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struct ArrayQueue {
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queue: Vec<i32>,
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head: i32,
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tail: i32,
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}
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impl ArrayQueue {
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fn new(n: usize) -> Self {
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ArrayQueue {
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queue: Vec::with_capacity(n),
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head: 0,
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tail: 0,
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}
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}
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fn enqueue(&mut self, num: i32) -> bool {
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let c = self.queue.capacity() as i32;
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// queue is full
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if self.head == 0 && self.tail == c { return false; }
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if self.tail == c {
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for i in 0..(self.tail-self.head) as usize {
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self.queue[i] = self.queue[self.head as usize + i];
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}
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self.tail -= self.head;
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self.head = 0;
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self.queue[self.tail as usize] = num;
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} else {
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self.queue.push(num);
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}
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self.tail += 1;
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true
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}
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fn dequeue(&mut self) -> i32 {
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if self.head == self.tail { return -1; }
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let shift = self.queue[self.head as usize];
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self.head += 1;
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shift
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}
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fn print_all(&self) {
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let mut s = String::from("");
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for i in self.head..self.tail {
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s.push(self.queue[i as usize] as u8 as char);
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s.push_str("->");
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}
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println!("{:?}", s);
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}
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}
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fn main() {
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let mut queue = ArrayQueue::new(3);
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queue.enqueue(2);
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queue.enqueue(2);
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queue.enqueue(2);
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queue.enqueue(2);
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queue.dequeue();
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queue.dequeue();
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queue.enqueue(4);
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queue.dequeue();
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queue.print_all();
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}
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