leetcode plusone problem solution

plusone.go

func plusOne(digits []int) []int {
    length := len(digits)-1
    var remain int
    firstSum := true
    for j:= length;j>=0;j--{
        var sum int
        if firstSum {
            sum = digits[j]+1
            firstSum = false
        }else{
            sum = digits[j]+remain
        }
        
        if sum> 9 {
            digits[j] = 0
            remain = 1
            continue
        }
        digits[j] = sum
        remain = 0
    }
    if remain> 0 {
        digits = append([]int{remain}, digits...)
    }
    return digits
}