├── a2b3c4.java
├── arrange_sentence_using_indexvalue.java
├── common substrings.java
├── hcf of 3 numbers.java
├── islands.java
├── islands2.java
├── lcm of 2 numbers.java
├── lcm of an array.java
├── permutation.java
├── reverse words.java
└── subarray.java


/a2b3c4.java:
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 1 | import java.util.*;
 2 | public class Main {
 3 |     public static void main(String[] args){
 4 |     Scanner sc=new Scanner(System.in);
 5 |     String s="a2b3c4";
 6 |     for(int i=0;i<s.length();i++)
 7 |     {
 8 |           char c=s.charAt(i);
 9 |           int m=(int)c-(int)'0';
10 |       if(m<9)
11 |       {
12 |         for(int j=0;j<m;j++)
13 |         {
14 |              System.out.print(s.charAt(i-1));
15 |         }
16 |       }
17 |     }
18 | }
19 | }
20 | //for two digit words
21 | *********************//
22 |     import java.util.*;
23 | public class Main {
24 |     public static void main(String[] args) {
25 |         Scanner sc = new Scanner(System.in);
26 |         System.out.print("Enter the String : ");
27 |         String str = sc.nextLine();
28 |         int n = str.length();
29 |         int num = 0;
30 |         for(int i=0;i<n-1;i++){
31 |             num = num*10 + (str.charAt(i) - '0');
32 |             char c = str.charAt(i+1);
33 |             if("0123456789".indexOf(c)==-1){
34 |                 String temp = "";
35 |                 for(int j=0;j<num;j++){
36 |                     temp += c;
37 |                 }
38 |                 System.out.print(temp);
39 |                 temp = "";
40 |                 num = 0;
41 |                 i++;
42 |             }
43 |         }
44 |         if(num!=0){
45 |             String temp = "";
46 |             for(int j=0;j<num;j++){
47 |                     temp += str.charAt(n-1);
48 |             }
49 |             System.out.print(temp);
50 |         }
51 |     }
52 | }
53 | 


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/arrange_sentence_using_indexvalue.java:
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 1 | import java.util.*;
 2 | public class Main{
 3 |     public static void main(String[] args)
 4 |     {
 5 |         Scanner sc=new Scanner(System.in);
 6 |         System.out.println("enter the sentence");
 7 |         String sentence = sc.nextLine();
 8 |         String[] words= sentence.split(" ");
 9 |         int a=words.length;
10 |         String[] ansstr=new String[a];
11 |         for(int i=0;i<a;i++)
12 |         {
13 |             String temp=words[i];
14 |             int lastpos=temp.length()-1;
15 |             int num=(int)temp.charAt(lastpos)-(int)'0';
16 |             String ans="";
17 |             for(int j=0;j<temp.length()-1;j++)
18 |             {
19 |                 ans=ans+temp.charAt(j);
20 |                 
21 |             }
22 |             ansstr[num]=ans;
23 |         }
24 |         
25 |         for(int i=0;i<ansstr.length;i++)
26 |         {
27 |             System.out.println("ans:"+ansstr[i]);
28 |         }
29 |     }
30 | }
31 | 


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/common substrings.java:
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 1 | import java.util.*;
 2 | class Main{
 3 |     public static void main(String[] args)
 4 |     {
 5 |         String[] arr={"geem","geekdd","geebdekefek","geerf"};
 6 |         Arrays.sort(arr);
 7 |         String s=arr[0];
 8 |         String s1=arr[arr.length-1];
 9 |         for(int i=0;i<s.length();i++)
10 |         {
11 |             if(s.charAt(i)==s1.charAt(i))
12 |             {
13 |                 System.out.print(s.charAt(i));
14 |             }
15 |             else{
16 |                 break;
17 |             }
18 |         }
19 |     }
20 | }
21 | 


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/hcf of 3 numbers.java:
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 1 | import java.util.*;
 2 | class hcf_3_numbers{
 3 |     public static int HCF(int a,int b)
 4 |     {
 5 |         while(b!=0)
 6 |         {
 7 |             int temp=b;
 8 |              b=a%b;
 9 |              a=temp;
10 |         }
11 |         return a;
12 |     }
13 |     
14 |     
15 |     
16 |     
17 |     public static void main(String[] args)
18 |     {
19 |         Scanner sc=new Scanner(System.in);
20 |         System.out.println("enter first number");
21 |         int a=sc.nextInt();
22 |         System.out.println("enter second number");
23 |         int b=sc.nextInt();
24 |         System.out.println("enter third number");
25 |         int c=sc.nextInt();
26 |         int ans=HCF(HCF(a,b),c);
27 |         System.out.println("HCF of "+a+" "+"and"+" "+b+ " "+ "is" +" "+ans );
28 |     }
29 | }
30 | 


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/islands.java:
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 1 | import java.util.*;
 2 | public class words{
 3 | public static void main(String[] args){
 4 | Scanner sc=new Scanner(System.in);
 5 | System.out.println("enter rows");
 6 | int row =sc.nextInt();
 7 | System.out.println("enter coiumns");
 8 | int col=sc.nextInt();
 9 | System.out.println("enter the elements");
10 | int[][] grid=new int[row][col];
11 | 
12 | for(int i=0;i<row;i++)
13 | {
14 |     for(int j=0;j<col;j++)
15 |     {
16 |         grid[i][j]=sc.nextInt();
17 |     }
18 | }
19 | System.out.println("No of Islands:"+islands(grid));
20 | }
21 | 
22 | public static int islands(int[][] grid)
23 | {
24 |     if(grid== null|| grid.length==0)
25 |     {
26 |         return 0;
27 |     }
28 |     int count=0;
29 |     int m=grid.length;
30 |     int n=grid[0].length;
31 |    for(int i=0;i<m;i++)
32 |    {
33 |       for(int j=0;j<n;j++)
34 |     {
35 |       if(grid[i][j]==1)
36 |       {
37 |         make0(grid,i,j);
38 |         count++;
39 |       }
40 |     }
41 |    }
42 |    return count;
43 | }
44 | 
45 | public static void make0(int[][] grid,int i,int j)
46 | {
47 |     if(i<0 || i>=grid.length || j<0 || j>=grid[0].length || grid[i][j]==0)
48 |     {
49 |         return;
50 |     }
51 |      grid[i][j]=0;
52 |    make0(grid,i+1,j);
53 |    make0(grid,i-1,j);
54 |    make0(grid,i,j+1);
55 |    make0(grid,i,j-1);
56 |     
57 | }
58 | }
59 | 


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/islands2.java:
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 1 | import java.util.*;
 2 | public class words{
 3 | public static void main(String[] args){
 4 | Scanner sc=new Scanner(System.in);
 5 | System.out.println("enter rows");
 6 | int row =sc.nextInt();
 7 | System.out.println("enter coiumns");
 8 | int col=sc.nextInt();
 9 | System.out.println("enter the elements");
10 | int[][] grid=new int[row][col];
11 | 
12 | for(int i=0;i<row;i++)
13 | {
14 |     for(int j=0;j<col;j++)
15 |     {
16 |         grid[i][j]=sc.nextInt();
17 |     }
18 | }
19 | System.out.println("No of Islands:"+islands(grid));
20 | }
21 | 
22 | public static int islands(int[][] grid)
23 | {
24 |     if(grid== null|| grid.length==0)
25 |     {
26 |         return 0;
27 |     }
28 |     int count=0;
29 |     int m=grid.length;
30 |     int n=grid[0].length;
31 |    for(int i=0;i<m;i++)
32 |    {
33 |       for(int j=0;j<n;j++)
34 |     {
35 |       if(grid[i][j]==1)
36 |       {
37 |         make0(grid,i,j);
38 |         count++;
39 |       }
40 |     }
41 |    }
42 |    return count;
43 | }
44 | 
45 | public static void make0(int[][] grid,int i,int j)
46 | {
47 |     if(i<0 || i>=grid.length || j<0 || j>=grid[0].length || grid[i][j]==0)
48 |     {
49 |         return;
50 |     }
51 |      grid[i][j]=0;
52 |    make0(grid,i+1,j);
53 |    make0(grid,i-1,j);
54 |    make0(grid,i,j+1);
55 |    make0(grid,i,j-1);
56 |    make0(grid,i+1,j+1);
57 |    make0(grid,i-1,j-1);
58 |    make0(grid,i-1,j+1);
59 |    make0(grid,i+1,j-1);
60 |     
61 | }
62 | }
63 | 


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/lcm of 2 numbers.java:
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 1 | import java.util.*;
 2 | class Main{
 3 |       public static int gcd(int a,int b)
 4 |       {
 5 |           while(b!=0)
 6 |           {
 7 |               int temp=b;
 8 |               b=a%b;
 9 |               a=temp;
10 |           }
11 |           return a;
12 |       }
13 |       
14 |       
15 |       public static void main(String[] args)
16 |       {
17 |           Scanner sc=new Scanner(System.in);
18 |           System.out.println("Enter first number");
19 |           int a=sc.nextInt();
20 |           System.out.println("Enter second number");
21 |           int b=sc.nextInt();
22 |           int c=gcd(a,b);
23 |           int d=(a*b)/c;
24 |           System.out.println("the lcm of two numbers is:"+d);
25 |       }
26 | }
27 | 


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/lcm of an array.java:
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 1 | import java.util.*;
 2 | class Main{
 3 |     public static void main(String[] args)
 4 |     {
 5 |         System.out.println("enter the no.of elements");
 6 |         Scanner sc=new Scanner(System.in);
 7 |         int n=sc.nextInt();
 8 |         int[] arr=new int[n];
 9 |         System.out.println("Enter the elements");
10 |         for(int i=0;i<n;i++)
11 |         {
12 |             arr[i]=sc.nextInt();
13 |         }
14 |         int d=lcmofarray(arr);
15 |         System.out.println("the lcm is:"+d);
16 |     }
17 |     
18 |     
19 |     public static int hcf(int a,int b)
20 |     {
21 |         while(b!=0)
22 |         {
23 |             int temp=b;
24 |             b=a%b;
25 |             a=temp;
26 |         }
27 |         return a;
28 |     }
29 |     
30 |     
31 |     public static int lcm(int a,int b){
32 |         int c=(a*b)/hcf(a,b);
33 |         return c;
34 |     }
35 |     
36 |     public static int lcmofarray(int[] arr)
37 |     {
38 |        int result=arr[0];
39 |         for(int i=0;i<arr.length;i++)
40 |         {
41 |             result=lcm(result,arr[i]);
42 |         }
43 |         return result;
44 |     }
45 | }
46 | 


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/permutation.java:
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 1 | 
 2 | import java.util.Scanner;
 3 | public class permutation {
 4 |   
 5 |     public static void permute(String str, String name) {
 6 |         if (str.length() == 0) {
 7 |             System.out.println(name);
 8 |         }
 9 |         else {
10 |             for (int i = 0; i < str.length(); i++) {
11 |                 String newStr = str.substring(0, i) + str.substring(i + 1);
12 |                 String newName = name + str.charAt(i);
13 |                 permute(newStr, newName);
14 |             }
15 |         }
16 |     }
17 |     public static void main(String[] args) {
18 |         Scanner sc = new Scanner(System.in);
19 |         String str= sc.nextLine();
20 |         permute(str, "");
21 | }
22 | }
23 | 


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/reverse words.java:
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 1 | import java.util.*;
 2 | class reverse_words{
 3 |   public static void main(String[] args)
 4 |   {
 5 |     Scanner sc=new Scanner(System.in);
 6 |     System.out.println("enter the sentence");
 7 |     String sentence=sc.nextLine();
 8 |     String reversedsentence=reversed_sentence(sentence);
 9 |     System.out.println("the reverse sentence is"+" "+reversedsentence);
10 |     
11 |     
12 |   }
13 |     
14 |    public static String reversed_sentence(String sentence)
15 |    {
16 |        String[] words=sentence.split(" ");
17 |        StringBuilder r=new StringBuilder();
18 |        for(int i=words.length-1;i>=0;i--)
19 |        {
20 |            r.append(words[i]).append(" ");
21 |        }
22 |      String m=  r.toString().trim();
23 |        return m;
24 |    }
25 |     
26 | }
27 | 


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/subarray.java:
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 1 | import java.util.*;
 2 | public class subarray {
 3 |     public static boolean subarray(int[] arr1,int[] arr2)
 4 |     {
 5 |              if(arr2.length==0)
 6 |              {
 7 |                 return true;
 8 |              }
 9 |              if(arr2.length>arr1.length)
10 |              {
11 |              return false;
12 |              }
13 |              for(int i=0;i<=arr1.length-arr2.length;i++)
14 |              {
15 |                 boolean match=true;
16 |                 for(int j=0;j<arr2.length;j++)
17 |                 {
18 |                     if(arr1[i+j]!=arr2[j])
19 |                     {
20 |                           match= false;
21 |                           break;
22 |                     }
23 |                 }
24 |                 if (match){
25 |                     return true;
26 |                 }
27 |              }
28 |              return false;
29 |     }
30 | 
31 |     public static void main(String[] args) {
32 |         Scanner sc=new Scanner(System.in);
33 |         int a=sc.nextInt();
34 |         int b=sc.nextInt();
35 |         int[]arr1=new int[a];
36 |         int[]arr2=new int[b];
37 |         for(int i=0;i<a;i++)
38 |         {
39 |             arr1[i]=sc.nextInt();
40 |         }
41 |         for(int i=0;i<b;i++)
42 |         {
43 |             arr2[i]=sc.nextInt();
44 |         }
45 |         boolean resullt=subarray(arr1,arr2);
46 |         System.out.println("the result after checking is"+resullt);
47 |     }
48 | }
49 | 


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