Contains Duplicate

Given an integer array nums, return true if any value appears at least twice in the array, and return false if every element is distinct. Source

package questions


import _utils.UseCommentAsDocumentation
import utils.shouldBe

/**
 * Given an integer array nums, return true if any value appears at least twice in the array,
 *  and return false if every element is distinct.
 * [Source](https://leetcode.com/problems/contains-duplicate/)
 */
@UseCommentAsDocumentation
private fun containsDuplicate(nums: IntArray): Boolean {
    if (nums.size == 1) {
        return false
    }
    val set = HashSet<Int>(nums.size)
    nums.forEach {
        if (set.contains(it)) {
            return true
        }
        set.add(it)
    }
    return false
}

private fun containsDuplicateFunc(nums: IntArray): Boolean {
    return nums.size != nums.distinct().size
}

fun main() {
    containsDuplicate(nums = intArrayOf(1, 2, 3, 1)) shouldBe true
    containsDuplicateFunc(nums = intArrayOf(1, 2, 3, 1)) shouldBe true

    containsDuplicate(nums = intArrayOf(1, 2, 3, 4)) shouldBe false
    containsDuplicateFunc(nums = intArrayOf(1, 2, 3, 4)) shouldBe false

    containsDuplicate(nums = intArrayOf(1, 1, 1, 3, 3, 4, 3, 2, 4, 2)) shouldBe true
    containsDuplicateFunc(nums = intArrayOf(1, 1, 1, 3, 3, 4, 3, 2, 4, 2)) shouldBe true
}

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Updated on 2021-10-21