Contains duplicate Problem

March 23, 2023

Name: Moch Lutfi
Twitter: @kaptenupi

Problem

Given an array of integers, write a function that determines whether the array contains any duplicates. Your function should return true if any element appears at least twice in the array, and it should return false if every element is distinct.

Example

For a = [1, 2, 3, 1], the output should be
solution(a) = true.

There are two 1s in the given array.
For a = [3, 1], the output should be
solution(a) = false.

The given array contains no duplicates.

Solution

Using HashSet

The solution is straightforward, create hash map to check if the array is duplicate or not.

use std::collections::HashSet;
fn solution(a: Vec<i32>) -> bool {
    let mut set= HashSet::new();
    for i in a{
        if !set.insert(i){
            return true;
        }
    }
    false
}

Or short version implementation above

use std::collections::HashSet;
fn solution(a: Vec<i32>) -> bool {
    let mut set = HashSet::new();
    a.into_iter().any(|x| !set.insert(x))
}

Using dedup function

This solution not using hash set but use sort and dedup

fn solution(mut a: Vec<i32>) -> bool {
    
    let original_length = a.len();
    a.sort();
    a.dedup();
    
    a.len() != original_length
}

See the vector docs (opens in a new tab) for the details internal function and how to use it.

Unit Testing in Golang Slice vs Array