Given a string str, the task is to find the length of the longest sub-string which does not have any pair of consecutive same characters.
Examples:
Input: str = “abcdde”
Output: 4
“abcd” is the longestInput: str = “ccccdeededff”
Output: 5
“ededf” is the longest
Approach: The following steps can be followed to solve the above problem:
- Initialize cnt and maxi as 1 initially, since this is the minimum answer of the length of the longest answer.
- Iterate in the string from 1 to n – 1 and increment cnt by 1 if str[i] != str[i – 1].
- If str[i] == str[i – 1], then re-initialize cnt as 1 and maxi to max(maxi, cnt).
Below is the implementation of the above approach:
C++
// C++ implementation of the approach #include <bits/stdc++.h> using namespace std; // Function to return the length // of the required sub-string int longestSubstring(string s) { int cnt = 1; int maxi = 1; // Get the length of the string int n = s.length(); // Iterate in the string for (int i = 1; i < n; i++) { // Check for not consecutive if (s[i] != s[i - 1]) cnt++; else { // If cnt greater than maxi maxi = max(cnt, maxi); // Re-initialize cnt = 1; } } // Check after iteration // is complete maxi = max(cnt, maxi); return maxi; } // Driver code int main() { string s = "ccccdeededff"; cout << longestSubstring(s); return 0; } |
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Java
// Java implementation of the approach import java.lang.Math; class GfG { // Function to return the length // of the required sub-string static int longestSubstring(String s) { int cnt = 1, maxi = 1; // Get the length of the string int n = s.length(); // Iterate in the string for (int i = 1; i < n; i++) { // Check for not consecutive if (s.charAt(i) != s.charAt(i-1)) cnt++; else { // If cnt greater than maxi maxi = Math.max(cnt, maxi); // Re-initialize cnt = 1; } } // Check after iteration is complete maxi = Math.max(cnt, maxi); return maxi; } // Driver code public static void main(String []args) { String s = "ccccdeededff"; System.out.println(longestSubstring(s)); } } // This code is contributed by Rituraj Jain |
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C#
// C# implementation of the approach using System; class GfG { // Function to return the length // of the required sub-string static int longestSubstring(string s) { int cnt = 1, maxi = 1; // Get the length of the string int n = s.Length; // Iterate in the string for (int i = 1; i < n; i++) { // Check for not consecutive if (s[i] != s[i - 1]) cnt++; else { // If cnt greater than maxi maxi = Math.Max(cnt, maxi); // Re-initialize cnt = 1; } } // Check after iteration is complete maxi = Math.Max(cnt, maxi); return maxi; } // Driver code static void Main() { string s = "ccccdeededff"; Console.WriteLine(longestSubstring(s)); } } // This code is contributed by mits |
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Python3
# Python3 implementation of the approach # Function to return the length # of the required sub-string def longestSubstring(s) : cnt = 1; maxi = 1; # Get the length of the string n = len(s); # Iterate in the string for i in range(1, n) : # Check for not consecutive if (s[i] != s[i - 1]) : cnt += 1; else : # If cnt greater than maxi maxi = max(cnt, maxi); # Re-initialize cnt = 1; # Check after iteration # is complete maxi = max(cnt, maxi); return maxi; # Driver code if __name__ == "__main__" : s = "ccccdeededff"; print(longestSubstring(s)); # This code is contirbuted by Ryuga |
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PHP
<?php // PHP implementation of the approach // Function to return the length // of the required sub-string function longestSubstring($s) { $cnt = 1; $maxi = 1; // Get the length of the string $n = strlen($s); // Iterate in the string for ($i = 1; $i < $n; $i++) { // Check for not consecutive if ($s[$i] != $s[$i - 1]) $cnt++; else { // If cnt greater than maxi $maxi = max($cnt, $maxi); // Re-initialize $cnt = 1; } } // Check after iteration // is complete $maxi = max($cnt, $maxi); return $maxi; } // Driver code $s = "ccccdeededff"; echo longestSubstring($s); // This code is contributed by Akanksha Rai ?> |
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Output:
5
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