剑指 Offer 17. 打印从1到最大的n位数

考虑大数的情况

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var res []int
var count int
func printNumbers(n int) []int{
    res = make([]int,int(math.Pow10(n)-1))
    count = 0
    for digit:=1; digit<=n;digit++{
        for first:='1';first<='9';first++{
            num := make([]byte,digit)
            num[0]=byte(first)
            dfs(1,num,digit)
        }
    }
    return res
}
func dfs(index int, num []byte, digit int){
    if index == digit{
        tmp,_ := strconv.Atoi(string(num))
        res[count] = tmp
        count ++
        return
    }
    for i:= '0'; i<='9';i++{
        num[index] = byte(i)
        dfs(index+1, num, digit)
    }
}