Problem Statement

Given an integer n greater than 0, return the n^th count-and-say sequence.

A count-and-say sequence is a string of digits created using specific rules given below.

• countAndSay(1) = "1"
• countAndSay(2) = say countAndSay(1)
• countAndSay(n) = say countAndSay(n - 1)

You start with "1", and for each subsequent string, you "read off" the digits of the previous string, counting the number of digits in groups of the same digit.

• For instance, say "1223" is read off as one 1 + two 2 + one 3 or 112213.

Examples

• Example 1:

  • Input: n = 3
  • Expected Output: "21"
  • Justification: The sequence is "1", "11" (one 1), "21" (two 1s).

• Example 2:

  • Input: n = 4
  • Expected Output: "1211"
  • Justification: Continuing from the last example, "21" is read as "one 2 + one 1" or "1211".

• Example 3:

  • Input: n = 5
  • Expected Output: "111221"
  • Justification: Continuing from the last example, "1211" is read as "one 1 + one 2 + two 1s" or "111221".

Try it yourself

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