# Count and Say Leetcode Solution

In this post, we are going to solve the Count and Say Leetcode Solution problem of Leetcode. This Leetcode problem is done in many programming languages like C++, Java, and Python.

## Problem

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 substrings such that each substring contains exactly one unique digit. Then for each substring, say the number of digits, then say the digit. Finally, concatenate every said digit.

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`

Now, lets see the leetcode solution of Count and Say Leetcode Solution.

### Count and Say Leetcode Solution in Python

```class Solution:
def countAndSay(self, n: int) -> str:
ans = '1'

for _ in range(n - 1):
nxt = ''
i = 0
while i < len(ans):
count = 1
while i + 1 < len(ans) and ans[i] == ans[i + 1]:
count += 1
i += 1
nxt += str(count) + ans[i]
i += 1
ans = nxt

return ans
```

### Count and SayLeetcode Solutionin CPP

```class Solution {
public:
string countAndSay(int n) {
string ans = "1";

while (--n) {
string next;
for (int i = 0; i < ans.length(); ++i) {
int count = 1;
while (i + 1 < ans.length() && ans[i] == ans[i + 1]) {
++count;
++i;
}
next += to_string(count) + ans[i];
}
ans = move(next);
}

return ans;
}
};
```

### Count and Say Leetcode Solution in Java

```class Solution {
public String countAndSay(int n) {
StringBuilder sb = new StringBuilder("1");

while (--n > 0) {
StringBuilder next = new StringBuilder();
for (int i = 0; i < sb.length(); ++i) {
int count = 1;
while (i + 1 < sb.length() && sb.charAt(i) == sb.charAt(i + 1)) {
++count;
++i;
}
next.append(count).append(sb.charAt(i));
}
sb = next;
}

return sb.toString();
}
}
```

Note: This problem Count and Say is generated by Leetcode but the solution is provided by Chase2learn This tutorial is only for Educational and Learning purposes.

NEXT: Combination Sum

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