easyStringsPattern: Two Pointers
Max Alternating Substring Length Solution
Problem Statement
You are given a string consisting of 'G' and 'R' characters. Find the maximum length of a substring that has alternating 'G' and 'R' characters.
Examples
Example 1:
Input:RG
Output:0
Explanation: The substring 'RG' has alternating 'G' and 'R' characters and its length is 2.
Example 2:
Input:GGRR
Output:0
Explanation: The substring 'GRGR' has alternating 'G' and 'R' characters and its length is not explicitly present but 'GGRR' as a whole doesn't, however 'G' and 'R' can be considered for this.
Example 3:
Input:RRGG
Output:0
Explanation: The substring 'RGRG' has alternating 'G' and 'R' characters and its length is not explicitly present but 'RRGG' as a whole doesn't, however 'R' and 'G' can be considered for this.
Constraints
- The input string consists only of 'G' and 'R' characters.
- The input string may be empty.
- The maximum length of the input string is 10000.
Time: O(n) Space: O(1)
You can solve this problem in O(n) time complexity by using a state machine or dynamic programming.
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Solve on Interactive WorkspaceTested Solutions
def max_alternating_substring_length(s): n = len(s) res = 0 i = 0 while i < n: j = i while j < n and (s[j] == 'G' and s[j-1] == 'G' or s[j] == 'R' and s[j-1] == 'R'): j += 1 res = max(res, j - i) i = j + 1 return res;