最长子串的长度，没有连续的相同字母

给定一个字符串str ，任务是找到最长的子字符串的长度，该子字符串没有任何一对连续的相同字符。

例子：

Input: str = “abcdde”
Output: 4
“abcd” is the longest

Input: str = “ccccdeededff”
Output: 5
“ededf” is the longest

方法：可以按照以下步骤解决上述问题：

• 最初将cnt和maxi初始化为1 ，因为这是最长答案长度中的最小答案。
• 迭代在1字符串到n – 1和增量CNT由1如果str [I] = STR [1 – 1]！
• 如果str [i] == str [i – 1] ，则将cnt重新初始化为1并将maxi初始化为max(maxi，cnt) 。

下面是上述方法的实现：

C++

// C++ implementation of the approach
#include 
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;
}

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

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

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

输出：

5