lib.txt

 
 1....Input formats
 static Scanner sc = new Scanner(System.in);
  
   static long l(){
        return sc.nextLong();
    }
    static int i(){
        return sc.nextInt();
    }
    static String s(){
        return sc.nextLine();
    }
	
	static int[] ia(int n){                                     //integer array urf ia()
      int arr[] = new int[n];
        
        for(int i=0;i<n;i++)
        arr[i] = i();
        return arr;
    }
	
	
	
	
	
	
	
	2...prime--returnns true if no. is prime--
	boolean prime(long num)               //returns true for prime numbers and false for non-primes
    {
       long i,limit =num/2 ;
	   if(num%2==0)
	   return false;
	   
       for(i=3;i<=limit;i+=2){
            
           if(num%i==0)
           return false;
        }
        return true;
     }
	 
	 
	 
	 
	 
	



3...
throws IOException
try{
        BufferedReader br = new BufferedReader (new InputStreamReader (System.in));
		int p = Integer.parseInt(input.readline());     //for int
		String y = input.readLine();       //for array
        String[] ar = y.split(" ");             //for array
      }
catch(IOException e){}
	 
	 

	 
	 
4...Hashmap

HashMap<String, Integer> map = new HashMap<String, Integer>();

Iterating hashmap
						for (Map.Entry<Integer, Integer> entry : map.entrySet()) 
						{
						System.out.println("Key = " + entry.getKey() + ", Value = " + entry.getValue());
						}
						
						
						
Iterating over keys only

						for (Integer key : map.keySet()) {
							System.out.println("Key = " + key);
						}

						
Iterating over values only
							
							for (Integer value : map.values()) {
								System.out.println("Value = " + value);
							}
						
						
						

						
						
						
5.ArrayList
             ArrayList<String> obj = new ArrayList<String>();
    
	Iterating arraylist
	         		for (String temp : obj) {
					System.out.println(temp);
					}
 

	

	
 6...exor...Find exor of all numbers in the range [a,b]

    long long f(long long a) {
			 long long res[] = {a,1,a+1,0};
			 return res[a%4];
}

long long getXor(long long a, long long b) {
     return f(b)^f(a-1);
}	 



7...  decimal to binary conversion

integer to binary number
String s =  Integer.toBinaryString(int);
binary to integer
int n = Integer.parseInt(BinaryString,2)



Long to binary
String s =  Long.toBinaryString(long);
binary to integer
long n = Long.parseLong(BinaryString,2)