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Added Ackermann function #794

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Merged
merged 2 commits into from
Nov 22, 2020
Merged

Added Ackermann function #794

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dc3778c
Ackermann added.
KrzysztofLukaszewicz Jul 17, 2019
3e1fbad
Ackermann updated
KrzysztofLukaszewicz Jul 17, 2019
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34 changes: 34 additions & 0 deletions src/main/java/com/others/Ackermann.java
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Original file line number Diff line number Diff line change
@@ -0,0 +1,34 @@
package src.main.java.com.others;


public class Ackermann {


/**
* Ackermann function - simplest and earliest-discovered examples of a total computable function
* that is not primitive recursive.
*
* Defined only for NONNEGATIVE integers !!!
*
* Time complexity is super-exponential. O(n(^))
* Any input m higher tahn (3,3) will result in StackOverflow
* @param m
* @param n
* @return
*
*
*/
public long Ack(long m, long n) {

if (m == 0)
return n + 1;

if (n == 0)
return Ack(m - 1, 1);

return Ack(m - 1, Ack(m, n - 1));
}

}


19 changes: 19 additions & 0 deletions src/test/java/com/others/AckermannTest.java
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package src.test.java.com.others;

import src.main.java.com.others.Ackermann;
import static org.junit.Assert.assertEquals;
import org.junit.Test;

public class AckermannTest {

@Test
public void testAckermann() {
Ackermann ackTest = new Ackermann();
assertEquals("Error", 1, ackTest.Ack(0, 0));
assertEquals("Error", 3, ackTest.Ack(1, 1));
assertEquals("Error", 7, ackTest.Ack(2, 2));
}



}