Leetcode 数组中重复的元素

func findDuplicates(nums []int) []int {
    margin := len(nums) + 1
    for _, num := range nums {
        nums[(num % margin) - 1] += margin
    }
    res := make([]int, 0)
    for idx, num := range nums {
        if num > 2 * margin {
            res = append(res, idx + 1)
        }
    }
    return res
}