countAndSay.go

package countAndSay

import "strconv"

//he count-and-say sequence is the sequence of integers with the first five terms as following:
//
//1.     1
//2.     11
//3.     21
//4.     1211
//5.     111221
//1 is read off as "one 1" or 11.
//11 is read off as "two 1s" or 21.
//21 is read off as "one 2, then one 1" or 1211.
//
//Given an integer n where 1 ≤ n ≤ 30, generate the nth term of the count-and-say sequence.
//
//Note: Each term of the sequence of integers will be represented as a string.
//
//
//
//Example 1:
//
//Input: 1
//Output: "1"
//Example 2:
//
//Input: 4
//Output: "1211"

func countAndSay(n int) string {
	readOff := "1"
	for i := 2; i <= n; i++ {
		readOff = say(readOff)
	}
	return readOff
}

func say(s string) string {
	var (
		result string
		tmp    byte
		count  int
	)
	for i := range s {
		if tmp != s[i] {
			if i != 0 {
				result += strconv.Itoa(count) + string(tmp)
			}
			tmp = s[i]
			count = 0
		}
		count++
		if i == len(s)-1 {
			result += strconv.Itoa(count) + string(tmp)
		}
	}
	return result
}