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Java Challange

Started by bratiefanut Apr 30, 2015 at 5:52 PM 4 replies 4.2k views

Original Post

Apr 30, 2015 at 5:52 PM

Ok guys,

Here is a challange for you :D.
The GOAL is to make a single separate .java file that calls CubicRootChallenge.checkCubicRoot() and is able to get true.

You are not able to use reflection.


import java.math.BigInteger;
import java.security.SecureRandom;
 
/**
 * RULES:
 *
 * <p>1. Write a class that by calling CubicRootChallenge.checkCubicRoot(), is able to reach the *GOAL* line
 *
 * <p>2. Solve the problem in a single separate .java file which compiles and runs with JDK 6/7/8
 *
 * <p>3. Your code must run with the security manager enabled (java -Djava.security.manager your.Class)
 *
 *
 */
public class CubicRootChallenge {
 
        // Number of BITS for the number
        public static final int BITS = 10000;
 
        // Generate random number with said bits [0 <--> 2^BITS - 1], and elevates it ^3
        private static final BigInteger NUMBER = new BigInteger(BITS, new SecureRandom()).pow(3);
 
        // Methods that prints out when passed BigInteger is cubic root of NUMBER
        public static void checkCubicRoot(BigInteger numberToTest) {
 
                // Check if numberToTest is cubic root of NUMBER
                if (NUMBER.divide(numberToTest).divide(numberToTest).equals(numberToTest)) {
 
                        // THE GOAL IS TO REACH THIS LINE!
                        System.out.println("YOU WIN!");
                }
        }
}

fastcall22

Mod

747

fastcall22

Apr 30, 2015 at 6:30 PM

public class Wat {
	public static void main(String[] args) {
		CubicRootChallenge.checkCubicRoot(new BigInteger("1"));
		System.out.println("YOU WIN!");
	}
}

deftware

104

deftware

Apr 30, 2015 at 6:37 PM


    fyl2x    
    fld st(0)
    frndint  
    fld1     
    fscale   
    fxch st(2)
    fsubrp   
    f2xm1    
    fld1     
    faddp    
    fmulp    
    ret

Datamancer

May 1, 2015 at 2:07 AM


    public class CubicRootChallenge {
        public static boolean checkCubicRoot() {
            return true;
        }
    }


public class Wat {
    public static void main( String[] arg ) {
        //I'll take my prize now ;)
        CubicRootChallenge.checkCubicRoot();
    }
}

ultramailman

May 1, 2015 at 5:49 AM

Ooo can somebody explain deftware's code? I didn't know .java files can look like that (looks like some kind of assembly?). How does it call checkCubicRoot? Also Mr L, are you accepting trick answers or are you really looking for a specific mathy solution?

Avalander

212

Avalander

May 1, 2015 at 12:18 PM


public static void main(String[] args) {
    while (true) {
        CubicRootChallenge.checkCubicRoot(new BigInteger(CubicRootChallenge.BITS, new SecureRandom()));
    }
}

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