/**
    Author : SUBHAM SANGHAI
    A Dynamic Programming based solution for Edit Distance problem In Java
    Edit distance is a way of quantifying how dissimilar two strings (e.g., words) are to one another, 
    by counting the minimum number of operations required to transform one string into the other
    **/
    import java.util.HashMap;
    import java.util.Map;
    import java.util.Scanner;
    public class Edit_Distance
    {
      public static int minDistance(String word1, String word2) 
      {
    	int len1 = word1.length();
    	int len2 = word2.length();
     	// len1+1, len2+1, because finally return dp[len1][len2]
    	int[][] dp = new int[len1 + 1][len2 + 1];
     
    	for (int i = 0; i <= len1; i++) 
    	{
    		dp[i][0] = i;
    	}
     
    	for (int j = 0; j <= len2; j++) 
    	{
    		dp[0][j] = j;
    	}
     	//iterate though, and check last char
    	for (int i = 0; i < len1; i++) 
    	{
    		char c1 = word1.charAt(i);
    		for (int j = 0; j < len2; j++) 
    		{
    			char c2 = word2.charAt(j);
     			//if last two chars equal
    			if (c1 == c2)
    			{
    				//update dp value for +1 length
    				dp[i + 1][j + 1] = dp[i][j];
    			} 
    			else 
    			{
    				int replace = dp[i][j] + 1;
    				int insert = dp[i][j + 1] + 1;
    				int delete = dp[i + 1][j] + 1;
     
    				int min = replace > insert ? insert : replace;
    				min = delete > min ? min : delete;
    				dp[i + 1][j + 1] = min;
    			}
    		}
    	}
    	return dp[len1][len2];
      }
    	// Driver program to test above function
    	public static void main(String args[])
    	{
    		Scanner input = new Scanner(System.in);
    		String s1,s2;
    		System.out.println("Enter the First String");
    		s1 = input.nextLine();
    		System.out.println("Enter the Second String");
    		s2 = input.nextLine();
    		//ans stores the final Edit Distance between the two strings
    		int ans=0;
    		ans=minDistance(s1,s2);
    		System.out.println("The minimum Edit Distance between \"" + s1 + "\" and \"" + s2 +"\" is "+ans);
    	}
    }