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feat: add solutions to lc problem: No.1912 (doocs#4735)
No.1912.Design Movie Rental System
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‎solution/1900-1999/1912.Design Movie Rental System/README.md‎

Lines changed: 295 additions & 11 deletions
Original file line numberDiff line numberDiff line change
@@ -87,38 +87,60 @@ movieRentingSystem.search(2); // 返回 [0, 1] 。商店 0 和 1 有未借出
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<!-- solution:start -->
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### 方法一
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### 方法一:有序集合
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我们定义一个有序集合 $\textit{available},ドル其中 $\textit{available}[movie]$ 存储所有未借出的电影 $movie$ 的商店列表,列表中的元素为 $(\textit{price}, \textit{shop}),ドル并按照 $\textit{price}$ 升序排序,如果 $\textit{price}$ 相同,则按照 $\textit{shop}$ 升序排序。
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另外定义一个哈希表 $\textit{price\_map},ドル其中 $\textit{price\_map}[f(\textit{shop}, \textit{movie})]$ 存储商店 $\textit{shop}$ 中电影 $\textit{movie}$ 的租借价格。
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我们还定义一个有序集合 $\textit{rented},ドル其中存储所有已借出的电影,元素为 $(\textit{price}, \textit{shop}, \textit{movie}),ドル并按照 $\textit{price}$ 升序排序,如果 $\textit{price}$ 相同,则按照 $\textit{shop}$ 升序排序,如果 $\textit{shop}$ 也相同,则按照 $\textit{movie}$ 升序排序。
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对于 $\text{MovieRentingSystem}(n, \text{entries})$ 操作,我们遍历 $\text{entries},ドル将每个商店的电影信息加入到 $\textit{available}$ 和 $\textit{price\_map}$ 中。时间复杂度为 $O(m \log m),ドル其中 $m$ 是 $\text{entries}$ 的长度。
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对于 $\text{search}(\text{movie})$ 操作,我们返回 $\textit{available}[\text{movie}]$ 中前 5 个商店的编号。时间复杂度为 $O(1)$。
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对于 $\text{rent}(\text{shop}, \text{movie})$ 操作,我们从 $\textit{available}[\text{movie}]$ 中移除 $(\textit{price}, \textit{shop}),ドル并将 $(\textit{price}, \textit{shop}, \textit{movie})$ 加入到 $\textit{rented}$ 中。时间复杂度为 $O(\log m)$。
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对于 $\text{drop}(\text{shop}, \text{movie})$ 操作,我们从 $\textit{rented}$ 中移除 $(\textit{price}, \textit{shop}, \textit{movie}),ドル并将 $(\textit{price}, \textit{shop})$ 加入到 $\textit{available}[\text{movie}]$ 中。时间复杂度为 $O(\log m)$。
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对于 $\text{report}()$ 操作,我们返回 $\textit{rented}$ 中前 5 个已借出电影的商店编号和电影编号。时间复杂度为 $O(1)$。
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空间复杂度为 $O(m)$。其中 $m$ 是 $\text{entries}$ 的长度。
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<!-- tabs:start -->
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#### Python3
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```python
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class MovieRentingSystem:
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def __init__(self, n: int, entries: List[List[int]]):
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self.unrented = collections.defaultdict(SortedList) # {movie: (price, shop)}
100-
self.shopAndMovieToPrice = {} # {(shop, movie): price}
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self.rented = SortedList() # (price, shop, movie)
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self.available = defaultdict(lambda: SortedList())
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self.price_map = {}
102120
for shop, movie, price in entries:
103-
self.unrented[movie].add((price, shop))
104-
self.shopAndMovieToPrice[(shop, movie)] = price
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self.available[movie].add((price, shop))
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self.price_map[self.f(shop, movie)] = price
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self.rented = SortedList()
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def search(self, movie: int) -> List[int]:
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return [shop for _, shop in self.unrented[movie][:5]]
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return [shop for _, shop in self.available[movie][:5]]
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def rent(self, shop: int, movie: int) -> None:
110-
price = self.shopAndMovieToPrice[(shop, movie)]
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self.unrented[movie].remove((price, shop))
129+
price = self.price_map[self.f(shop, movie)]
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self.available[movie].remove((price, shop))
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self.rented.add((price, shop, movie))
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def drop(self, shop: int, movie: int) -> None:
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price = self.shopAndMovieToPrice[(shop, movie)]
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self.unrented[movie].add((price, shop))
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price = self.price_map[self.f(shop, movie)]
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self.rented.remove((price, shop, movie))
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self.available[movie].add((price, shop))
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def report(self) -> List[List[int]]:
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return [[shop, movie] for _, shop, movie in self.rented[:5]]
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def f(self, shop: int, movie: int) -> int:
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return shop << 30 | movie
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# Your MovieRentingSystem object will be instantiated and called as such:
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# obj = MovieRentingSystem(n, entries)
@@ -128,6 +150,268 @@ class MovieRentingSystem:
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# param_4 = obj.report()
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```
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#### Java
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```java
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class MovieRentingSystem {
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private Map<Integer, TreeSet<int[]>> available = new HashMap<>();
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private Map<Long, Integer> priceMap = new HashMap<>();
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private TreeSet<int[]> rented = new TreeSet<>((a, b) -> {
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if (a[0] != b[0]) {
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return a[0] - b[0];
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}
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if (a[1] != b[1]) {
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return a[1] - b[1];
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}
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return a[2] - b[2];
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});
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public MovieRentingSystem(int n, int[][] entries) {
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for (int[] entry : entries) {
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int shop = entry[0], movie = entry[1], price = entry[2];
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available
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.computeIfAbsent(movie, k -> new TreeSet<>((a, b) -> {
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if (a[0] != b[0]) {
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return a[0] - b[0];
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}
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return a[1] - b[1];
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}))
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.add(new int[] {price, shop});
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priceMap.put(f(shop, movie), price);
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}
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}
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public List<Integer> search(int movie) {
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List<Integer> res = new ArrayList<>();
186+
if (!available.containsKey(movie)) {
187+
return res;
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}
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int cnt = 0;
190+
for (int[] item : available.get(movie)) {
191+
res.add(item[1]);
192+
if (++cnt == 5) {
193+
break;
194+
}
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}
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return res;
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}
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199+
public void rent(int shop, int movie) {
200+
int price = priceMap.get(f(shop, movie));
201+
available.get(movie).remove(new int[] {price, shop});
202+
rented.add(new int[] {price, shop, movie});
203+
}
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public void drop(int shop, int movie) {
206+
int price = priceMap.get(f(shop, movie));
207+
rented.remove(new int[] {price, shop, movie});
208+
available.get(movie).add(new int[] {price, shop});
209+
}
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211+
public List<List<Integer>> report() {
212+
List<List<Integer>> res = new ArrayList<>();
213+
int cnt = 0;
214+
for (int[] item : rented) {
215+
res.add(Arrays.asList(item[1], item[2]));
216+
if (++cnt == 5) {
217+
break;
218+
}
219+
}
220+
return res;
221+
}
222+
223+
private long f(int shop, int movie) {
224+
return ((long) shop << 30) | movie;
225+
}
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}
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/**
229+
* Your MovieRentingSystem object will be instantiated and called as such:
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* MovieRentingSystem obj = new MovieRentingSystem(n, entries);
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* List<Integer> param_1 = obj.search(movie);
232+
* obj.rent(shop,movie);
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* obj.drop(shop,movie);
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* List<List<Integer>> param_4 = obj.report();
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*/
236+
```
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#### C++
239+
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```cpp
241+
class MovieRentingSystem {
242+
private:
243+
unordered_map<int, set<pair<int, int>>> available; // movie -> {(price, shop)}
244+
unordered_map<long long, int> priceMap;
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set<tuple<int, int, int>> rented; // {(price, shop, movie)}
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long long f(int shop, int movie) {
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return ((long long) shop << 30) | movie;
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}
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public:
252+
MovieRentingSystem(int n, vector<vector<int>>& entries) {
253+
for (auto& e : entries) {
254+
int shop = e[0], movie = e[1], price = e[2];
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available[movie].insert({price, shop});
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priceMap[f(shop, movie)] = price;
257+
}
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}
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vector<int> search(int movie) {
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vector<int> res;
262+
if (!available.count(movie)) {
263+
return res;
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}
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int cnt = 0;
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for (auto& [price, shop] : available[movie]) {
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res.push_back(shop);
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if (++cnt == 5) {
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break;
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}
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}
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return res;
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}
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void rent(int shop, int movie) {
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int price = priceMap[f(shop, movie)];
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available[movie].erase({price, shop});
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rented.insert({price, shop, movie});
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}
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void drop(int shop, int movie) {
282+
int price = priceMap[f(shop, movie)];
283+
rented.erase({price, shop, movie});
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available[movie].insert({price, shop});
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}
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vector<vector<int>> report() {
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vector<vector<int>> res;
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int cnt = 0;
290+
for (auto& [price, shop, movie] : rented) {
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res.push_back({shop, movie});
292+
if (++cnt == 5) {
293+
break;
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}
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}
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return res;
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}
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};
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/**
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* Your MovieRentingSystem object will be instantiated and called as such:
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* MovieRentingSystem* obj = new MovieRentingSystem(n, entries);
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* vector<int> param_1 = obj->search(movie);
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* obj->rent(shop,movie);
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* obj->drop(shop,movie);
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* vector<vector<int>> param_4 = obj->report();
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*/
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```
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#### Go
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```go
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type MovieRentingSystem struct {
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available map[int]*treeset.Set // movie -> (price, shop)
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priceMap map[int64]int
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rented *treeset.Set // (price, shop, movie)
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}
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func Constructor(n int, entries [][]int) MovieRentingSystem {
320+
// comparator for (price, shop)
321+
cmpAvail := func(a, b any) int {
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x := a.([2]int)
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y := b.([2]int)
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if x[0] != y[0] {
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return x[0] - y[0]
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}
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return x[1] - y[1]
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}
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// comparator for (price, shop, movie)
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cmpRented := func(a, b any) int {
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x := a.([3]int)
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y := b.([3]int)
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if x[0] != y[0] {
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return x[0] - y[0]
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}
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if x[1] != y[1] {
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return x[1] - y[1]
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}
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return x[2] - y[2]
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}
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mrs := MovieRentingSystem{
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available: make(map[int]*treeset.Set),
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priceMap: make(map[int64]int),
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rented: treeset.NewWith(cmpRented),
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}
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for _, e := range entries {
349+
shop, movie, price := e[0], e[1], e[2]
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if _, ok := mrs.available[movie]; !ok {
351+
mrs.available[movie] = treeset.NewWith(cmpAvail)
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}
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mrs.available[movie].Add([2]int{price, shop})
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mrs.priceMap[f(shop, movie)] = price
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}
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return mrs
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}
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func (this *MovieRentingSystem) Search(movie int) []int {
361+
res := []int{}
362+
if _, ok := this.available[movie]; !ok {
363+
return res
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}
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it := this.available[movie].Iterator()
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it.Begin()
367+
cnt := 0
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for it.Next() && cnt < 5 {
369+
pair := it.Value().([2]int)
370+
res = append(res, pair[1])
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cnt++
372+
}
373+
return res
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}
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func (this *MovieRentingSystem) Rent(shop int, movie int) {
377+
price := this.priceMap[f(shop, movie)]
378+
this.available[movie].Remove([2]int{price, shop})
379+
this.rented.Add([3]int{price, shop, movie})
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}
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func (this *MovieRentingSystem) Drop(shop int, movie int) {
383+
price := this.priceMap[f(shop, movie)]
384+
this.rented.Remove([3]int{price, shop, movie})
385+
this.available[movie].Add([2]int{price, shop})
386+
}
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func (this *MovieRentingSystem) Report() [][]int {
389+
res := [][]int{}
390+
it := this.rented.Iterator()
391+
it.Begin()
392+
cnt := 0
393+
for it.Next() && cnt < 5 {
394+
t := it.Value().([3]int)
395+
res = append(res, []int{t[1], t[2]})
396+
cnt++
397+
}
398+
return res
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}
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func f(shop, movie int) int64 {
402+
return (int64(shop) << 30) | int64(movie)
403+
}
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/**
406+
* Your MovieRentingSystem object will be instantiated and called as such:
407+
* obj := Constructor(n, entries);
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* param_1 := obj.Search(movie);
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* obj.Rent(shop,movie);
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* obj.Drop(shop,movie);
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* param_4 := obj.Report();
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*/
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```
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<!-- tabs:end -->
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<!-- solution:end -->

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