use std::collections::HashMap;

struct Solution {}

impl Solution {
    pub fn contains_nearby_duplicate(nums: Vec<i32>, k: i32) -> bool {
        let mut map = HashMap::new();
        for (ind, val) in nums.iter().enumerate() {
            let prev = map.entry(val).or_insert(ind);
            let dist = ind - *prev;
            if dist != 0 {
                if dist <= k as usize {
                    return true;
                } else {
                    *prev = ind;
                }
            }
        }
        false
    }
}

fn main() {
    assert!(Solution::contains_nearby_duplicate(vec![1,2,3,1], 3));
}