You have a movie renting company consisting of n shops. You want to implement a renting system that supports searching for, booking, and returning movies. The system should also support generating a report of the currently rented movies.
Each movie is given as a 2D integer array entries where entries[i] = [shopi, moviei, pricei] indicates that there is a copy of movie moviei at shop shopi with a rental price of pricei. Each shop carries at most one copy of a movie moviei.
The system should support the following functions:
- Search: Finds the cheapest 5 shops that have an unrented copy of a given movie. The shops should be sorted by price in ascending order, and in case of a tie, the one with the smaller
shopishould appear first. If there are less than 5 matching shops, then all of them should be returned. If no shop has an unrented copy, then an empty list should be returned. - Rent: Rents an unrented copy of a given movie from a given shop.
- Drop: Drops off a previously rented copy of a given movie at a given shop.
- Report: Returns the cheapest 5 rented movies (possibly of the same movie ID) as a 2D list
reswhereres[j] = [shopj, moviej]describes that thejthcheapest rented moviemoviejwas rented from the shopshopj. The movies inresshould be sorted by price in ascending order, and in case of a tie, the one with the smallershopjshould appear first, and if there is still tie, the one with the smallermoviejshould appear first. If there are fewer than 5 rented movies, then all of them should be returned. If no movies are currently being rented, then an empty list should be returned.
Implement the MovieRentingSystem class:
MovieRentingSystem(int n, int[][] entries)Initializes theMovieRentingSystemobject withnshops and the movies inentries.List<Integer> search(int movie)Returns a list of shops that have an unrented copy of the givenmovieas described above.void rent(int shop, int movie)Rents the givenmoviefrom the givenshop.void drop(int shop, int movie)Drops off a previously rentedmovieat the givenshop.List<List<Integer>> report()Returns a list of cheapest rented movies as described above.
Note: The test cases will be generated such that rent will only be called if the shop has an unrented copy of the movie, and drop will only be called if the shop had previously rented out the movie.
Input: ["MovieRentingSystem", "search", "rent", "rent", "report", "drop", "search"] [[3, [[0, 1, 5], [0, 2, 6], [0, 3, 7], [1, 1, 4], [1, 2, 7], [2, 1, 5]]], [1], [0, 1], [1, 2], [], [1, 2], [2]] Output: [null, [1, 0, 2], null, null, [[0, 1], [1, 2]], null, [0, 1]] Explanation: MovieRentingSystem movieRentingSystem = new MovieRentingSystem(3, [[0, 1, 5], [0, 2, 6], [0, 3, 7], [1, 1, 4], [1, 2, 7], [2, 1, 5]]); movieRentingSystem.search(1); // return [1, 0, 2], Movies of ID 1 are unrented at shops 1, 0, and 2. Shop 1 is cheapest; shop 0 and 2 are the same price, so order by shop number. movieRentingSystem.rent(0, 1); // Rent movie 1 from shop 0. Unrented movies at shop 0 are now [2,3]. movieRentingSystem.rent(1, 2); // Rent movie 2 from shop 1. Unrented movies at shop 1 are now [1]. movieRentingSystem.report(); // return [[0, 1], [1, 2]]. Movie 1 from shop 0 is cheapest, followed by movie 2 from shop 1. movieRentingSystem.drop(1, 2); // Drop off movie 2 at shop 1. Unrented movies at shop 1 are now [1,2]. movieRentingSystem.search(2); // return [0, 1]. Movies of ID 2 are unrented at shops 0 and 1. Shop 0 is cheapest, followed by shop 1.
1 <= n <= 3 * 1051 <= entries.length <= 1050 <= shopi < n1 <= moviei, pricei <= 104- Each shop carries at most one copy of a movie
moviei. - At most
105calls in total will be made tosearch,rent,dropandreport.
use std::cmp::Reverse;
use std::collections::BinaryHeap;
use std::collections::HashMap;
struct MovieRentingSystem {
rented: HashMap<(i32, i32), (bool, i32)>,
search_heaps: HashMap<i32, BinaryHeap<Reverse<(i32, i32)>>>,
report_heap: BinaryHeap<Reverse<(i32, i32, i32)>>,
}
/**
* `&self` means the method takes an immutable reference.
* If you need a mutable reference, change it to `&mut self` instead.
*/
impl MovieRentingSystem {
fn new(n: i32, entries: Vec<Vec<i32>>) -> Self {
let mut rented = HashMap::new();
let mut search_heaps = HashMap::new();
for i in 0..entries.len() {
let (shop, movie, price) = (entries[i][0], entries[i][1], entries[i][2]);
rented.insert((shop, movie), (false, price));
search_heaps
.entry(movie)
.or_insert(BinaryHeap::new())
.push(Reverse((price, shop)));
}
Self {
rented: rented,
search_heaps: search_heaps,
report_heap: BinaryHeap::new(),
}
}
fn search(&mut self, movie: i32) -> Vec<i32> {
let mut empty = BinaryHeap::new();
let mut heap = self.search_heaps.get_mut(&movie).unwrap_or(&mut empty);
let mut res = vec![];
while let Some(Reverse((price, shop))) = heap.pop() {
if !self.rented[&(shop, movie)].0 && shop != *res.last().unwrap_or(&-1) {
res.push(shop);
}
if res.len() == 5 {
break;
}
}
for &shop in &res {
heap.push(Reverse((self.rented[&(shop, movie)].1, shop)));
}
res
}
fn rent(&mut self, shop: i32, movie: i32) {
self.rented.get_mut(&(shop, movie)).unwrap().0 = true;
self.report_heap
.push(Reverse((self.rented[&(shop, movie)].1, shop, movie)));
}
fn drop(&mut self, shop: i32, movie: i32) {
self.rented.get_mut(&(shop, movie)).unwrap().0 = false;
self.search_heaps
.get_mut(&movie)
.unwrap()
.push(Reverse((self.rented[&(shop, movie)].1, shop)));
}
fn report(&mut self) -> Vec<Vec<i32>> {
let mut res = vec![];
while let Some(Reverse((price, shop, movie))) = self.report_heap.pop() {
if self.rented[&(shop, movie)].0 && &vec![shop, movie] != res.last().unwrap_or(&vec![])
{
res.push(vec![shop, movie]);
}
if res.len() == 5 {
break;
}
}
for i in 0..res.len() {
let (shop, movie) = (res[i][0], res[i][1]);
self.report_heap
.push(Reverse((self.rented[&(shop, movie)].1, shop, movie)));
}
res
}
}
/**
* Your MovieRentingSystem object will be instantiated and called as such:
* let obj = MovieRentingSystem::new(n, entries);
* let ret_1: Vec<i32> = obj.search(movie);
* obj.rent(shop, movie);
* obj.drop(shop, movie);
* let ret_4: Vec<Vec<i32>> = obj.report();
*/