LeetCode/rs/unique-number-of-occurrences.rs

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Rust
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use std::collections::{HashMap, HashSet};
impl Solution {
pub fn unique_occurrences(arr: Vec<i32>) -> bool {
// count frequencies
let mut freqs: HashMap<i32, i32> = HashMap::new();
for x in &arr {
*freqs.entry(*x).or_insert(0) += 1;
}
freqs.values().collect::<HashSet<_>>().len() == freqs.len()
}
}