90 lines
2.8 KiB
Java
90 lines
2.8 KiB
Java
/**
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Author : SUBHAM SANGHAI
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A Dynamic Programming based solution for Edit Distance problem In Java
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**/
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/**Description of Edit Distance with an Example:
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Edit distance is a way of quantifying how dissimilar two strings (e.g., words) are to one another,
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by counting the minimum number of operations required to transform one string into the other. The
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distance operations are the removal, insertion, or substitution of a character in the string.
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The Distance between "kitten" and "sitting" is 3. A minimal edit script that transforms the former into the latter is:
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kitten → sitten (substitution of "s" for "k")
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sitten → sittin (substitution of "i" for "e")
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sittin → sitting (insertion of "g" at the end).**/
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import java.util.Scanner;
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public class Edit_Distance
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{
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public static int minDistance(String word1, String word2)
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{
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int len1 = word1.length();
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int len2 = word2.length();
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// len1+1, len2+1, because finally return dp[len1][len2]
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int[][] dp = new int[len1 + 1][len2 + 1];
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/* If second string is empty, the only option is to
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insert all characters of first string into second*/
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for (int i = 0; i <= len1; i++)
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{
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dp[i][0] = i;
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}
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/* If first string is empty, the only option is to
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insert all characters of second string into first*/
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for (int j = 0; j <= len2; j++)
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{
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dp[0][j] = j;
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}
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//iterate though, and check last char
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for (int i = 0; i < len1; i++)
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{
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char c1 = word1.charAt(i);
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for (int j = 0; j < len2; j++)
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{
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char c2 = word2.charAt(j);
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//if last two chars equal
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if (c1 == c2)
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{
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//update dp value for +1 length
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dp[i + 1][j + 1] = dp[i][j];
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}
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else
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{
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/* if two characters are different ,
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then take the minimum of the various operations(i.e insertion,removal,substitution)*/
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int replace = dp[i][j] + 1;
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int insert = dp[i][j + 1] + 1;
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int delete = dp[i + 1][j] + 1;
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int min = replace > insert ? insert : replace;
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min = delete > min ? min : delete;
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dp[i + 1][j + 1] = min;
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}
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}
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}
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/* return the final answer , after traversing through both the strings*/
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return dp[len1][len2];
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}
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// Driver program to test above function
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public static void main(String args[])
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{
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Scanner input = new Scanner(System.in);
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String s1,s2;
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System.out.println("Enter the First String");
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s1 = input.nextLine();
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System.out.println("Enter the Second String");
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s2 = input.nextLine();
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//ans stores the final Edit Distance between the two strings
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int ans=0;
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ans=minDistance(s1,s2);
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System.out.println("The minimum Edit Distance between \"" + s1 + "\" and \"" + s2 +"\" is "+ans);
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}
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}
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