# Count and Say LeetCode Solution

·2 mins
leetcode Author
Mayukh Datta

The count-and-say sequence is a sequence of digit strings defined by the recursive formula:

• `countAndSay(1) = "1"`
• `countAndSay(n)` is the way you would “say” the digit string from `countAndSay(n-1)`, which is then converted into a different digit string.

To determine how you “say” a digit string, split it into the minimal number of groups so that each group is a contiguous section all of the same character. Then for each group, say the number of characters, then say the character. To convert the saying into a digit string, replace the counts with a number and concatenate every saying.

For example, the saying and conversion for digit string `"3322251"`:

Given a positive integer `n`, return the `nth` term of the count-and-say sequence.

Example 1:

Input: n = 1 Output: “1” Explanation: This is the base case.

Example 2:

Input: n = 4 Output: “1211” Explanation: countAndSay(1) = “1” countAndSay(2) = say “1” = one 1 = “11” countAndSay(3) = say “11” = two 1’s = “21” countAndSay(4) = say “21” = one 2 + one 1 = “12” + “11” = “1211”

Constraints:

• `1 <= n <= 30`

## Solution #

class Solution { public: string countAndSay(int n) {

``````    // base case
if(n == 1) {
return "1";
}

string result = "1";

for(int i=2;i<=n;i++) {
char previous = result\[0\];
string temp = "";
int count = 1;

for(int j=1;j<=result.length();j++) {
if(result\[j\] != previous) {
temp = temp + to\_string(count) + previous;
previous = result\[j\];
count = 1;
}else{
count++;
}
}
result = temp;
}

return result;
}
``````

};