LeetCode Entry

2053. Kth Distinct String in an Array

05.08.2024 easy 2024 kotlin rust

kth unique

2053. Kth Distinct String in an Array easy blog post substack youtube 1.webp

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Problem TLDR

kth unique #easy

Intuition

Filter out all the duplicates first.

Approach

We can use a HashMap for counter or just two HashSets. Let’s use some API:

  • Kotlin: groupingBy.eachCount, filter
  • Rust: filter, skip, next

Complexity

  • Time complexity: \(O(n)\)

  • Space complexity: \(O(1)\)

Code


    fun kthDistinct(arr: Array<String>, k: Int) = arr
        .groupingBy { it }.eachCount().filter { it.value == 1 }
        .keys.elementAtOrNull(k - 1) ?: ""


    pub fn kth_distinct(arr: Vec<String>, k: i32) -> String {
        let (mut uniq, mut dup) = (HashSet::new(), HashSet::new());
        for s in &arr { if !uniq.insert(s) { dup.insert(s); }}
        arr.iter().filter(|&s| !dup.contains(s)).skip(k as usize - 1)
           .next().unwrap_or(&"".to_string()).to_string()
    }