2024-03-25 16:23:11 +0000 UTC

func findDuplicates(nums []int) []int {
    output := []int{}
    for _, num := range nums {
        idx := abs(num)
        if nums[idx-1] < 0 {
            output = append(output, idx)
        } else {
            nums[idx-1] *= -1
        }
    }
    return output
}
func abs(num int) int {
    if num < 0 {
        return -num
    }
    return num
}