Leetcode 645 Set Mismatch.go

func findErrorNums(nums []int) []int {
    sum, duplicate := 0, 0
    n := len(nums)
    numsMap := make(map[int]bool, n)
    for _, num := range nums {
        if numsMap[num] == true {
            duplicate = num
        }
        sum += num
        numsMap[num] = true
    }
    // sort.Ints(nums)
    // for i:=0; i<n-1; i++ {
    //     if nums[i] == nums[i+1] {
    //         duplicate = nums[i]
    //     }
    //     sum += nums[i]
    // }
    // sum += nums[n-1]
    return []int{duplicate, ((n*(n+1)/2)-sum+duplicate) }
}