SubString and SubArrays And Permutations of Stirngs

Author: mangesh-balkawade

src/strings/SubSet.java

@@ -0,0 +1,127 @@
+package strings;
+
+import java.util.ArrayList;
+import java.util.List;
+
+public class SubSet {
+
+//Normal fakt string cut karat jato
+static void subSeq(String temp, String str) {
+if (str.length() == 0) {
+System.out.println(temp);
+return;
+}
+subSeq(temp + str.charAt(0), str.substring(1));
+subSeq(temp, str.substring(1));
+}
+
+// ARraylist return
+static ArrayList<String> subSeq2(String temp, String str,ArrayList< String> list) {
+if (str.length() == 0) {
+list.add(temp);
+return list ;
+}
+subSeq(temp + str.charAt(0), str.substring(1));
+subSeq(temp, str.substring(1));
+return list;
+}
+
+
+static List<List<Integer>> SubArray(int arr[])
+{
+List<List<Integer>> outer=new ArrayList<List<Integer>>();
+ArrayList<Integer> list=new ArrayList<>();
+outer.add(list);
+
+// Each element of array should be added in the each element present inside the 
+// previous list;
+
+for(int num:arr)
+{
+// Taken Size here because we are adding elments in the loop 
+int size=outer.size();
+
+// Adding each element of array in previous lists.
+
+for(int i=0;i<size;i++)
+{
+ ArrayList<Integer> internal=new ArrayList<>();
+ internal.addAll(outer.get(i));
+ internal.add(num);
+ outer.add(internal);
+}
+}
+
+
+return outer;
+
+}
+
+
+static void permutations(String temp,String str)
+{
+if(str.length()==0)
+{
+System.out.println(temp);
+return ;
+}
+// Taken the character ;
+char ch=str.charAt(0);
+
+// Each time the no of recursions we have to made are = size of temp + 1;
+// The character can be add at 3 pos eg
+// AB & /C rem.
+// _AB A_B AB_ = CAB ACB ABC
+for(int i=0;i<=temp.length();i++)
+{
+String first=temp.substring(0,i);
+String second=temp.substring(i);
+permutations(first+ch+second, str.substring(1));
+}
+}
+
+static ArrayList<String> permutations2(String temp,String str,ArrayList<String>list)
+{
+if(str.length()==0)
+{
+ list.add(temp);
+return list;
+}
+char ch=str.charAt(0);
+for(int i=0;i<=temp.length();i++)
+{
+String first=temp.substring(0,i);
+String second=temp.substring(i);
+permutations(first+ch+second, str.substring(1));
+}
+return list;
+}
+
+public static void main(String[] args) {
+
+System.out.println("---------Printing the subsequences of strings-----------");
+ subSeq("","ABC");
+ 
+ System.out.println("---------Arraylist the subsequences of strings-----------");
+ArrayList<String> list1= subSeq2("","ABC", new ArrayList<String>());
+for (String string : list1) {
+System.out.println(string);
+}
+
+System.out.println("---------Printing the Sub Arrays -----------");
+int arr[]= {1,2,3};
+System.out.println(SubArray(arr));
+
+System.out.println("---------Printing the Permutations of strings-----------");
+permutations("","ABC");
+
+System.out.println("---------Printing the Permutations of strings-----------");
+ArrayList<String> list2=permutations2("","ABC", new ArrayList<>());
+for (String string : list2) {
+System.out.println(string);
+}
+
+
+
+}
+}