주간문제 HashMap

vec_decl.rs

use std::slice::SliceIndex;
use std::ptr::NonNull;
use std::ops::{Deref, DerefMut, Index, IndexMut};
use std::iter::FromIterator;

// 필드는 참고용이며 꼭 이렇게 안해도됨
pub struct Vec<T> {
    ptr: NonNull<T>,
    len: usize,
    cap: usize,
}

// 필수 api
impl<T> Vec<T> {
    pub fn new() -> Self;
    pub fn with_capacity(capacity: usize) -> Self;
    pub fn len(&self) -> usize;
    pub fn get(&self) -> Option<&T>;
    pub fn get_mut(&mut self) -> Option<&mut T>;
    pub fn push(&mut self, val: T);
    pub fn pop(&mut self) -> Option<T>;
    pub fn clear(&mut self);
}

// 필수 trait 구현
impl<T, I> Index<I> for Vec<T> where I: SliceIndex<[T]> { type Output = T; }
impl<T, I> IndexMut<I> for Vec<T> where I: SliceIndex<[T]> {}
impl<T> Deref for Vec<T> { type Target = [T]; }
impl<T> DerefMut for Vec<T> {}
impl<T> Clone for Vec<T> where T: Clone {}
impl<T> IntoIterator for Vec<T> {}
impl<T> FromIterator<T> for Vec<T> {}

// 자동구현이 되는 경우엔 생략
unsafe impl<T> Send for Vec<T> where T: Send {}
unsafe impl<T> Sync for Vec<T> where T: Sync {}


// 통과해야할 테스트들
#[cfg(test)]
mod tests {
    use super::Vec;
    
    #[test]
    #[should_panic]
    fn out_of_bound() {
        let v = Vec::<i32>::new();
        v[123];
    }

    #[test]
    fn make_vec() {
        let v: Vec<usize> = (0..100).collect();
        for i in 0..100 {
            assert_eq!(v[i], i);
        }
    }

    #[test]
    fn push_test() {
        let mut v = Vec::new();
        v.push(1);
        v.push(654);
        v.push(123);
        v.push(654);
        v.pop();
        assert_eq!(&v[..], &[1, 654, 123]);
    }
}