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Linked List Create in java.

  package L inked L ist ; class Node {     int val ;     Node next ;     Node ( int val ){         this . val = val ;     } } public class ListNodeClass { // print function using temp node public static void print ( Node head ){ Node temp = head ; while ( temp != null ){     System . out . println ( temp . val );     temp = temp . next ; } } // print list reverse order using recursion public static void dispRevRec ( Node head ){ if ( head == null ) return ; dispRevRec ( head . next ); System . out . println ( head . val ); } // print list using recursion public static void dispRec ( Node head ){ if ( head == null ) return ; System . out . println ( head . val ); dispRec ( head . next ); } public static void main ( String [] args ) { Node a = new Node ( 10 ); Node b = new Node ( 20 ); Node c = new Node ( 30 ); Node d = new Node ( 40 ); Node e = new Node ( 50 );...

Single Linked List in java.

package L inked L ist ; class sll {     Node head ;     Node tail ;     int size ; void printSize (){     System . out . println ( "size is = " + size ); } void print (){ if ( head == null ){     System . out . println ( "List is empty" );     return ; } System . out . println ( "linked list is =>" ); Node temp = head ; while ( temp != null ){     System . out . print ( temp . val + " " );     temp = temp . next ; } System . out . println (); } void deleteAtStart (){ if ( head == null ){     System . out . println ( "list is empty" );     return ; } // only one node if ( head == tail ){     head = tail = null ; } else {     head = head . next ; }     size -- ; } void deleteAtIndex ( int ix ){     if ( ix < 0 || ix >= size ){     throw new RuntimeException ( "invalid index" );     }     if ( ix ...

substring function in java.

  package program ; import java . util .* ; public class code {     public static void main ( String [] args ) {     Scanner sc = new Scanner ( System . in );     System . out . println ( "enter srting=" );     String s = sc . nextLine ();     String t = "" ;     System . out . println ( "enter value of i=" );     int i = sc . nextInt ();     for ( int j = i ; j < s . length (); j ++ ){         t += s . charAt ( j );     }     System . out . println ( "substring is =" + t );    } } // function 2 -> package program ; import java . util .* ; public class code {     public static void main ( String [] args ) {     Scanner sc = new Scanner ( System . in );     System . out . println ( "enter srting=" );     String s = sc . nextLine ();     String t = "" ;     ...

String Convert into Upper case in java.

  package program ; import java . util .* ; public class code {     public static void main ( String [] args ) {     Scanner sc = new Scanner ( System . in );     System . out . println ( "enter srting=" );     String s = sc . nextLine ();     String t = "" ;     for ( int i = 0 ; i < s . length (); i ++ ){         int as = s . charAt ( i );         if ( as >= 97 && as <= 122 ){             as -= 32 ;             t += ( char ) as ;         }         else             t += s . charAt ( i );     }     System . out . println ( "Upper case string is=" + t );    } }

String change into Lower Case in java.

  package program ; import java . util .* ; public class code {     public static void main ( String [] args ) {     Scanner sc = new Scanner ( System . in );     System . out . println ( "enter srting=" );     String s = sc . nextLine ();     String t = "" ;     for ( int i = 0 ; i < s . length (); i ++ ){         int as = s . charAt ( i );         if ( as >= 65 && as <= 90 ){             as += 32 ;             t += ( char ) as ;         }         else             t += s . charAt ( i );     }     System . out . println ( "lower case string is=" + t );    } }

compare two string in java without built-in function.

  import java . util .* ; public class code {     public static void main ( String [] args ) {     Scanner sc = new Scanner ( System . in );       System . out . println ( "enter string 1=" );       String s = sc . nextLine ();       System . out . println ( "enter string 2=" );       String t = sc . nextLine ();       boolean flag = true ;       int ans = 0 ;       int i = 0 , j = 0 ;       while ( i < s . length () && j < t . length ()){             int as1 = s . charAt ( i );             int as2 = t . charAt ( j );             if ( as1 != as2 ){             flag = false ;             ans = ( as1 - as2 );             break ;   ...

Find Last index of character in sting in Java.

  import java . util .* ; public class code {     public static void main ( String [] args ) {     Scanner sc = new Scanner ( System . in );       System . out . println ( "enter string=" );       String s = sc . nextLine ();       System . out . println ( "enter character=" );       char ch = sc . next (). charAt ( 0 );       boolean flag = false ;       int index =- 1 ;       for ( int i = s . length () - 1 ; i >= 0 ; i -- ){         if ( ch == s . charAt ( i )){         index = i ;         flag = true ;         break ;         }      }       if ( flag == false )         System . out . println ( "character is not present in string" );       else         Sys...

Find First Index of character in string in Java .

  import java . util .* ; public class code {     public static void main ( String [] args ) {     Scanner sc = new Scanner ( System . in );       System . out . println ( "enter string=" );       String s = sc . nextLine ();       System . out . println ( "enter character=" );       char ch = sc . next (). charAt ( 0 );       boolean flag = false ;       int index =- 1 ;       for ( int i = 0 ; i < s . length (); i ++ ){         if ( ch == s . charAt ( i )){         index = i ;         flag = true ;         break ;         }      }       if ( flag == false )         System . out . println ( "character is not present in string" );       else         System . ...

Count number of vowel in a given string in Java.

  import java . util .* ; public class code {     public static void main ( String [] args ) {     Scanner sc = new Scanner ( System . in );       System . out . println ( "enter string=" );       String s = sc . nextLine ();       int vow = 0 ;       for ( int i = 0 ; i < s . length (); i ++ ){         char ch = s . charAt ( i );         if ( ch == 'a' || ch == 'e' || ch == 'i' || ch == 'o' || ch == 'u' || ch == 'A' || ch == 'E' || ch == 'I' || ch == 'O' || ch == 'U' )             vow ++ ;      }       System . out . println ( "total vowel in string are=" + vow );     } } // method 2-> import java . util .* ; public class code {     public static void main ( String [] args ) {     Scanner sc = new Scanner ( System . in );     ...

Convert String into character array in java.

  import java . util .* ; public class code {     public static void main ( String [] args ) {     Scanner sc = new Scanner ( System . in );       System . out . println ( "enter string=" );       String s = sc . nextLine ();       System . out . println ( "enter index=" );       int x = sc . nextInt ();     // char[] crr=s.toCharArray(); [string convert into character array]     char [] crr = new char [ s . length ()];     for ( int i = 0 ; i < s . length (); i ++ ){         crr [ i ] = s . charAt ( i );      }       System . out . println ( crr [ x ]);     } }

sorting question.

 Given an array with N distinct elements all are positive , convert the given array to a form where all elements are in the range from 0 to N-1. The order of elements is the same, i.e., 0 is placed in the place of the smallest element, 1 is placed for the second smallest element, ... N-1 is placed for the largest element. public class code {     public static void main ( String [] args ) {         int [] arr = { 54 , 11 , 28 , 47 , 91 , 63 };         int n = arr . length ;         int x = 0 ;         for ( int i = 0 ; i < n ; i ++ ){             int mn = Integer . MAX_VALUE ;             int ix =- 1 ;             for ( int j = 0 ; j < n ; j ++ ){                 if ( arr [ j ] < mn && arr [ j ] > 0 ){         ...

Binary search in java.

  import java . util .* ; public class code {     public static void main ( String [] args ) {         Scanner sc = new Scanner ( System . in );         System . out . println ( "enter size of array=" );         int n = sc . nextInt ();         int [] arr = new int [ n ];         System . out . println ( "enter elements of array in sorted manner=" );         for ( int i = 0 ; i < n ; i ++ ){             arr [ i ] = sc . nextInt ();         }         System . out . println ( "enter target=" );         int target = sc . nextInt ();         int low = 0 , high = n - 1 ;         boolean flag = false ;         while ( low <= high ){             int mid = ( low ...

Transform array in java.

 Given an array with N distinct all are positive elements, convert the given array to a form where all elements are in the range from 0 to N-1. The order of elements is the same, i.e., 0 is placed in the place of the smallest element, 1 is placed for the second smallest element, … N-1 is placed for the largest element.   import java . util . Scanner ; public class code {     public static void main ( String [] args ) {     Scanner sc = new Scanner ( System . in );     System . out . println ( "enter size of array=" );     int n = sc . nextInt ();     int [] arr = new int [ n ];     System . out . println ( "enter elements of array=" );     for ( int i = 0 ; i < n ; i ++ ){         arr [ i ] = sc . nextInt ();     }     int x = 0 ;     for ( int i = 0 ; i < n ; i ++ ){         int min = Integer . MAX_VALUE ; ...