diff --git a/Dynamic Programming/Edit_Distance.java b/Dynamic Programming/Edit_Distance.java new file mode 100644 index 000000000..00835bc5c --- /dev/null +++ b/Dynamic Programming/Edit_Distance.java @@ -0,0 +1,69 @@ + /** + 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); + } + } diff --git a/Dynamic Programming/Fibonacci.java b/Dynamic Programming/Fibonacci.java index 17c11d8d6..b2524b4db 100644 --- a/Dynamic Programming/Fibonacci.java +++ b/Dynamic Programming/Fibonacci.java @@ -11,7 +11,7 @@ import java.util.Map; public class Fibonacci { - public static Map map = new HashMap(); + private static Map map = new HashMap(); public static void main(String[] args) throws Exception { @@ -29,7 +29,7 @@ public class Fibonacci { * Outputs the nth fibonacci number **/ - public static int fibMemo(int n) { + private static int fibMemo(int n) { if (map.containsKey(n)) { return map.get(n); } @@ -54,7 +54,7 @@ public class Fibonacci { * Outputs the nth fibonacci number **/ - public static int fibBotUp(int n) { + private static int fibBotUp(int n) { Map fib = new HashMap(); diff --git a/Dynamic Programming/Levenshtein_distance.java b/Dynamic Programming/Levenshtein_distance.java index 5bff389fb..49f399020 100644 --- a/Dynamic Programming/Levenshtein_distance.java +++ b/Dynamic Programming/Levenshtein_distance.java @@ -7,7 +7,7 @@ */ public class Levenshtein_distance{ - private int minimum(int a, int b, int c){ + private static int minimum(int a, int b, int c){ if(a < b && a < c){ return a; }else if(b < a && b < c){ @@ -16,7 +16,7 @@ public class Levenshtein_distance{ return c; } } - public int calculate_distance(String a, String b){ + private static int calculate_distance(String a, String b){ len_a = a.length() + 1; len_b = b.length() + 1; int [][] distance_mat = new int[len_a][len_b]; diff --git a/Dynamic Programming/LongestIncreasingSubsequence.java b/Dynamic Programming/LongestIncreasingSubsequence.java index 1616c246e..eaa574a40 100644 --- a/Dynamic Programming/LongestIncreasingSubsequence.java +++ b/Dynamic Programming/LongestIncreasingSubsequence.java @@ -31,7 +31,7 @@ public class LongestIncreasingSubsequence { return r; } - public static int LIS(int[] array) { + private static int LIS(int[] array) { int N = array.length; if (N == 0) return 0;