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| // @Title: 用两个栈实现队列 (用两个栈实现队列 LCOF)
// @Author: 15816537946@163.com
// @Date: 2022-01-31 11:28:26
// @Runtime: 60 ms
// @Memory: 4.7 MB
// 第9题的第二种题解, 借鉴网上的答案
#[derive(Default)]
struct CQueue {
p: Vec<i32>,
q: Vec<i32>,
}
/**
* `&self` means the method takes an immutable reference.
* If you need a mutable reference, change it to `&mut self` instead.
*/
impl CQueue {
fn new() -> Self {
Default::default()
}
fn append_tail(&mut self, value: i32) {
self.p.push(value);
}
fn delete_head(&mut self) -> i32 {
match self.q.pop() {
Some(v) => v,
None => {
self.p.reverse();
self.q.append(&mut self.p);
self.q.pop().unwrap_or(-1)
}
}
}
}
/*
* Your CQueue object will be instantiated and called as such:
* let obj = CQueue::new();
* obj.append_tail(value);
* let ret_2: i32 = obj.delete_head();
*/
|