Single Number III

Given an integer array nums, in which exactly two elements appear only once and all the other elements appear exactly twice. Find the two elements that appear only once. You can return the answer in any order.

Source

package questions

import _utils.UseCommentAsDocumentation
import utils.assertIterableSameInAnyOrder

/**
 * Given an integer array nums, in which exactly two elements appear only once and
 * all the other elements appear exactly twice.
 * Find the two elements that appear only once. You can return the answer in any order.
 *
 * [Source](https://leetcode.com/problems/single-number-iii/)
 */
@UseCommentAsDocumentation
private fun singleNumber(nums: IntArray): IntArray {
    if (nums.size == 2) return nums
    val record = mutableSetOf<Int>()
    for (i in 0..nums.lastIndex) {
        val element = nums[i]
        if (record.contains(element)) {
            record.remove(element)
        } else {
            record.add(element)
        }
    }
    return intArrayOf(record.elementAt(0), record.elementAt(1))
}

fun main() {
    assertIterableSameInAnyOrder(intArrayOf(3, 5).toList(), singleNumber(intArrayOf(1, 2, 1, 3, 2, 5)).toList())
    assertIterableSameInAnyOrder(listOf(-1, 0), singleNumber(intArrayOf(-1, 0)).toList())
}

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Updated on 2021-10-13