100 lines
2.4 KiB
Rust
100 lines
2.4 KiB
Rust
/**
|
|
* [2671] Frequency Tracker
|
|
*/
|
|
pub struct Solution {}
|
|
|
|
// submission codes start here
|
|
use std::collections::{HashMap, HashSet};
|
|
|
|
struct FrequencyTracker {
|
|
number_map: HashMap<i32, i32>,
|
|
frequency_map: HashMap<i32, HashSet<i32>>,
|
|
}
|
|
|
|
/**
|
|
* `&self` means the method takes an immutable reference.
|
|
* If you need a mutable reference, change it to `&mut self` instead.
|
|
*/
|
|
impl FrequencyTracker {
|
|
fn new() -> Self {
|
|
FrequencyTracker {
|
|
number_map: HashMap::new(),
|
|
frequency_map: HashMap::new(),
|
|
}
|
|
}
|
|
|
|
fn add(&mut self, number: i32) {
|
|
let mut entry = self.number_map.entry(number).or_insert(0);
|
|
|
|
if *entry != 0 {
|
|
if let Some(set) = self.frequency_map.get_mut(&entry) {
|
|
set.remove(&number);
|
|
}
|
|
}
|
|
|
|
*entry += 1;
|
|
let set = self.frequency_map.entry(*entry).or_insert(HashSet::new());
|
|
set.insert(number);
|
|
}
|
|
|
|
fn delete_one(&mut self, number: i32) {
|
|
if let Some(entry) = self.number_map.get_mut(&number) {
|
|
if *entry == 0 {
|
|
return;
|
|
}
|
|
|
|
if let Some(set) = self.frequency_map.get_mut(&entry) {
|
|
set.remove(&number);
|
|
}
|
|
|
|
*entry -= 1;
|
|
let set = self.frequency_map.entry(*entry).or_insert(HashSet::new());
|
|
set.insert(number);
|
|
}
|
|
}
|
|
|
|
fn has_frequency(&self, frequency: i32) -> bool {
|
|
let set = self.frequency_map.get(&frequency);
|
|
|
|
match set {
|
|
Some(set) => set.len() != 0,
|
|
None => false,
|
|
}
|
|
}
|
|
}
|
|
|
|
/**
|
|
* Your FrequencyTracker object will be instantiated and called as such:
|
|
* let obj = FrequencyTracker::new();
|
|
* obj.add(number);
|
|
* obj.delete_one(number);
|
|
* let ret_3: bool = obj.has_frequency(frequency);
|
|
*/
|
|
|
|
// submission codes end
|
|
|
|
#[cfg(test)]
|
|
mod tests {
|
|
use super::*;
|
|
|
|
#[test]
|
|
fn test_2671() {
|
|
let mut tracker = FrequencyTracker::new();
|
|
|
|
tracker.add(10);
|
|
tracker.delete_one(5);
|
|
assert!(tracker.has_frequency(1));
|
|
tracker.delete_one(10);
|
|
tracker.delete_one(9);
|
|
tracker.delete_one(10);
|
|
assert!(!tracker.has_frequency(1));
|
|
tracker.add(4);
|
|
assert!(tracker.has_frequency(1));
|
|
tracker.delete_one(4);
|
|
assert!(!tracker.has_frequency(1));
|
|
assert!(!tracker.has_frequency(1));
|
|
tracker.add(10);
|
|
assert!(tracker.has_frequency(1));
|
|
}
|
|
}
|