finds minimum operation to make two String equal, add/replace/remove allowed

Author: NirmalSilwal

Interview Prep/section19_DynamicProgramming/EditDistance.java

@@ -0,0 +1,38 @@
+package section19_DynamicProgramming;
+
+public class EditDistance {
+
+	public static void main(String[] args) {
+
+		String s1 = "agbg";
+		String s2 = "acgb";
+
+		System.out.println(editDistance(s1, s2)); // 2
+	}
+
+	// minimum changes required to make s2 equal to s1
+	public static int editDistance(String s1, String s2) {
+
+		if (s1.length() == 0)
+			return s2.length();
+
+		if (s2.length() == 0)
+			return s1.length();
+
+		String ros1 = s1.substring(1);
+		String ros2 = s2.substring(1);
+		int result = 0;
+
+		if (s1.charAt(0) == s2.charAt(0)) {
+			result = editDistance(ros1, ros2);
+		} else {
+			int removeFactor = 1 + editDistance(ros1, ros2);
+			int addFactor = 1 + editDistance(ros1, s2);
+			int replaceFactor = 1 + editDistance(s1, ros2);
+
+			result = Math.min(removeFactor, Math.min(addFactor, replaceFactor));
+		}
+
+		return result;
+	}
+}