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Java Lambda Expressions

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  • Damian_GDO_92
     + 0 comments
    import java.io.*;
import java.util.*;
interface PerformOperation {
 boolean check(int a);
}
class MyMath {
 public static boolean checker(PerformOperation p, int num) {
  return p.check(num);
 }

 public static PerformOperation isOdd() {
    return i -> {
      return i % 2 != 0 ? true : false;
    };
 }

 public PerformOperation isPrime() {
    return i -> {
      if (i == 2) return true;
      if (i <= 1 || i % 2 == 0) return false;
      
      int numberSqrt = (int)Math.sqrt(i);

      for (int j=3; j<=numberSqrt; j+=2) {
        if (i % j == 0) return false;
      }
      return true;
    };
 }

 public static PerformOperation isPalindrome() {
    return i -> {
      String numberStr = String.valueOf(i);
      String reversedStr = "";
      
      for (int j=numberStr.length()-1; j>=0; j--) {
        reversedStr += numberStr.charAt(j);
      }

      return numberStr.equals(reversedStr);
    }; 
 }
}

public class Solution {

 public static void main(String[] args) throws IOException {
  MyMath ob = new MyMath();
  BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
  int T = Integer.parseInt(br.readLine());
  PerformOperation op;
  boolean ret = false;
  String ans = null;
  while (T--> 0) {
   String s = br.readLine().trim();
   StringTokenizer st = new StringTokenizer(s);
   int ch = Integer.parseInt(st.nextToken());
   int num = Integer.parseInt(st.nextToken());
   if (ch == 1) {
    op = ob.isOdd();
    ret = ob.checker(op, num);
    ans = (ret) ? "ODD" : "EVEN";
   } else if (ch == 2) {
    op = ob.isPrime();
    ret = ob.checker(op, num);
    ans = (ret) ? "PRIME" : "COMPOSITE";
   } else if (ch == 3) {
    op = ob.isPalindrome();
    ret = ob.checker(op, num);
    ans = (ret) ? "PALINDROME" : "NOT PALINDROME";

   }
   System.out.println(ans);
  }
 }
}

  • spriyamalar
     + 0 comments

    public static PerformOperation isOdd() { return (num) -> num%2!=0; }

    public static PerformOperation isPrime() { return (num) -> java.math.BigInteger.valueOf(num).isProbablePrime(100); }

    public static PerformOperation isPalindrome() { return num -> num == reverseNum(num); }

    private static int reverseNum(int num) { int result = 0; while(num > 0) { int val = num%10; result = (result * 10) + val; num = num/10; } return result; }

  • yashdeora98294
     + 0 comments

    Here is Java Lambda Expressions solution in Java - https://programmingoneonone.com/hackerrank-java-lambda-expressions-problem-solution.html

  • Ahmed_Wafik
     + 1 comment

    Java 8 Solution:-

    import java.io.*;
import java.util.*;

interface PerformOperation {
    boolean check(int a);
}

class MyMath {
    public static boolean checker(PerformOperation p, int num) {
        return p.check(num);
    }

    public PerformOperation isOdd() {
        return a -> a % 2 != 0;
    }

    public PerformOperation isPrime() {
        return a -> {
            if (a <= 1)
                return false;
            if (a == 2 || a == 3)
                return true;

            if (a % 2 == 0 || a % 3 == 0)
                return false;

            for (int i = 5; i <= Math.sqrt(a); i = i + 6)
                if (a % i == 0 || a % (i + 2) == 0)
                    return false;
            return true;

        };
    }

    public PerformOperation isPalindrome() {

        return a -> {
            String s = "" + a;
            int i = 0, j = s.length() - 1;

            while (i < j) {
                if (s.charAt(i) != s.charAt(j)) {
                    return false;
                }
                i++;
                j--;
            }
            return true;
        };
    }


}


// Write your code here

public class Solution {

    public static void main(String[] args) throws IOException {
        MyMath ob = new MyMath();
        BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
        int T = Integer.parseInt(br.readLine());
        PerformOperation op;
        boolean ret = false;
        String ans = null;
        while (T-- > 0) {
            String s = br.readLine().trim();
            StringTokenizer st = new StringTokenizer(s);
            int ch = Integer.parseInt(st.nextToken());
            int num = Integer.parseInt(st.nextToken());
            if (ch == 1) {
                op = ob.isOdd();
                ret = ob.checker(op, num);
                ans = (ret) ? "ODD" : "EVEN";
            } else if (ch == 2) {
                op = ob.isPrime();
                ret = ob.checker(op, num);
                ans = (ret) ? "PRIME" : "COMPOSITE";
            } else if (ch == 3) {
                op = ob.isPalindrome();
                ret = ob.checker(op, num);
                ans = (ret) ? "PALINDROME" : "NOT PALINDROME";

            }
            System.out.println(ans);
        }
    }
}

  • seftimarket
     + 0 comments

    My solution:

    interface Predicate{

    boolean test(int a);

    } public class Solution {

    public static void main(String[] args) {

    Scanner scan = new Scanner(System.in);
    int full = scan.nextInt();
    while(full--> 0){
        int code = scan.nextInt();
        int number = scan.nextInt();
        if (code==1){
            boolean a = op(n-> isOdd(n), number);
        System.out.println(a==true?"EVEN":"ODD");
        }else if(code==2){
               boolean a = op(n-> isPrime(n), number);
        System.out.println(a==true?"PRIME":"COMPOSITE");
        }else{
               boolean a = op(n-> isPalindrome(n), number);
        System.out.println(a==true?"PALINDROME":"NOT PALINDROME");
        }
    }
}
static boolean op(Predicate<Integer> predi, int number) {
    return predi.test(number);

}
static boolean isPrime(int number) {
    for(int i=2;i<(int)Math.sqrt(number);i++){
        if(number%i==0) return false;
    }
    return true;
}
static boolean isPalindrome(int number) {
    String c = ""+number;
    StringBuilder b = new StringBuilder(c).reverse();
    int d = Integer.parseInt(b.toString());
    return number==d;
}

static boolean isOdd(int number) {
    return number%2==0;
}

    }