Minimum distance between duplicates in a String

// Java program for the above approach
import java.io.*;

class GFG{
  
// This function is used to find
// minimum distance between same
// repeating characters
static int shortestDistance(String S, int N)
{
    
    // Store minimum distance between same
    // repeating characters
    int minDis = S.length();
  
    // For loop to consider each element
    // of string
    for(int i = 0; i < N; i++)
    {
        for(int j = i + 1; j < N; j++) 
        {
            
            // Comparison of string characters and
            // updating the minDis value
            if (S.charAt(i) == S.charAt(j) && 
               (j - i) < minDis)
            {
                minDis = j - i;
                
                // As this value would be least
                // therefore break
                break;
            }
        }
    }
  
    // If minDis value is not updated that means
    // no repeating characters
    if (minDis == S.length())
        return -1;
  
    // Minimum distance is minDis - 1
    else
        return minDis - 1;
}

// Driver code
public static void main(String[] args)
{
    
    // Given input
    String S = "geeksforgeeks";
    int N = 13;
  
    // Function call
    System.out.println(shortestDistance(S, N));
}
}

// This code is contributed by MuskanKalra1

// Java implementation of above approach
import java.io.*;
import java.util.*;

class GFG{

// This function is used to find
// minimum distance between same
// repeating characters
static int shortestDistance(String S, int N)
{
    
    // Define a hashmap and an arraylist
    HashMap<Character, 
            Integer> dic = new HashMap<Character, 
                                       Integer>();
    ArrayList<Integer> dis = new ArrayList<>();

    // Temporary variable
    int var;

    // Traverse through string
    for(int i = 0; i < N; i++) 
    {
        
        // If character present in dictionary
        if (dic.get(S.charAt(i)) != null) 
        {
            
            // Difference between current position
            // and last stored value
            var = i - dic.get(S.charAt(i));
            
            // Updating current position
            dic.put(S.charAt(i), i);
            
            // Storing difference in list
            dis.add(var);
        }

        // If character not in dictionary assign
        // it with initial of its position
        else 
        {
            dic.put(S.charAt(i), i);
        }
    }

    // If no element inserted in list
    // i.e. no repeating characterss
    if (dis.size() == 0)
        return -1;

    // Return minimum distance
    else
        return Collections.min(dis) - 1;
}

// Driver code
public static void main(String[] args)
{
    
    // Given input
    String S = "geeksforgeeks";
    int N = 13;

    // Function call
    System.out.println(shortestDistance(S, N));
}
}

// This code is contributed by MuskanKalra1

// Java Program to find the minimum distance between two
// repeating characters in a String using two pointers
// technique
import java.util.*;

class GFG {

    // This function is used to find
    // minimum distance between any two
    // repeating characters
    // using two - pointers and hashing technique
    static int shortestDistance(String s, int n)
    {

        // hash array to store character's last index
        int[] visited = new int[128];
        Arrays.fill(visited, -1);
        int ans = Integer.MAX_VALUE;

        // Traverse through the String
        for (int right = 0; right < n; right++) {
            char c = s.charAt(right);
            int left = visited[c];

            // If the character is present in visited array
            // find if its forming minimum distance
            if (left != -1)
                ans = Math.min(ans, right - left - 1);

            // update current character's last index
            visited[c] = right;
        }
      
        // Return minimum distance found, else -1
        return ans == Integer.MAX_VALUE ? -1 : ans;
    }

  // Driver code
    public static void main(String[] args)
    {
      
        // Given Input
        String s = "geeksforgeeks";
        int n = 13;

        // Function Call
        System.out.print(shortestDistance(s, n));
    }
}

// This code is contributed by umadevi9616