update

src/src/main/java/StringManipulation.java

@@ -0,0 +1,66 @@
+import java.util.*;
+
+public class StringManipulation implements StringManipulationInterface {
+    private String s;
+
+    @Override
+    public void setString(String s) {
+        this.s = s;
+    }
+
+    @Override
+    public int count() {
+        if (s == null || s.length() == 0) {
+            return 0;
+        }
+        return s.trim().split("\\s+").length;
+    }
+
+    @Override
+    public String removeNthCharacter(int n, boolean includeSpaces) {
+        StringBuilder result = new StringBuilder();
+
+        for (int i = 0; i < s.length(); i++) {
+            char c = s.charAt(i);
+
+            if ((includeSpaces && c != ' ') || !includeSpaces) {
+                if ((i + 1) % n != 0) {
+                    result.append(c);
+                } else if (includeSpaces) {
+                    result.append(' ');
+                }
+            } else {
+                result.append(c);
+            }
+        }
+
+        return result.toString();
+    }
+
+
+    @Override
+    public String[] getSubStrings(int start, int end) {
+        if (s == null || s.length() == 0) {
+            return new String[0];
+        }
+        String[] words = s.split("\\s+");
+        if (start < 0 || end > words.length || start > end) {
+            return new String[0];
+        }
+        return Arrays.copyOfRange(words, start, end+1);
+    }
+
+    @Override
+    public String restoreString(int[] array) {
+        if (s == null || array == null) {
+            return s;
+        }
+        char[] arr = new char[s.length()];
+        for (int i = 0; i < array.length; i++) {
+            if (array[i] < arr.length) {
+                arr[array[i]] = s.charAt(i);
+            }
+        }
+        return new String(arr);
+    }
+}

src/src/main/java/StringManipulationInterface.java

@@ -0,0 +1,16 @@
+public interface StringManipulationInterface {
+    // Method to set the string
+    void setString(String s);
+
+    // Method to count the number of words in the string
+    int count();
+
+    // Method to remove the nth character from the string, considering spaces as well or not
+    String removeNthCharacter(int n, boolean considerSpaces);
+
+    // Method to get an array of substrings of the string, from start to end (both inclusive)
+    String[] getSubStrings(int start, int end);
+
+    // Method to restore the string by the provided array
+    String restoreString(int[] array);
+}