Find First Repeated Character in a String

Given a string 'STR' composed of lowercase English letters, identify the character that repeats first in terms of its initial occurrence.

Example:

Input:

STR = "abccba"

Output:

"a"

Explanation:

Although the first repeating character is 'c', the character 'a' is the first repeated character by initial appearance.

Constraints:

1

Question

Find First Repeated Character in a String

Given a string 'STR' composed of lowercase English letters, identify the character that repeats first in terms of its initial occurrence.

Example:

Input:

STR = "abccba"

Output:

"a"

Explanation:

Although the first repeating character is 'c', the character 'a' is the first repeated character by initial appearance.

Constraints:

1 <= T <= 200
0 <= length of S <= 10000
‘S’ consists of lowercase English alphabets.

In the scenario where no repeated character exists, output '%'.

Note:

Ensure that you return the repeated character that appears first, rather than simply the first character that repeats. If there are no repeating characters, return '%'. The function to implement is called “repeatedCharacter”.

Accepted Answer

Find the first repeated character in a given string of lowercase English letters.

Iterate through the string and keep track of characters seen so far
Return the first character that repeats, if none, return '%'
Use a hash set or array to store characters seen