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rootulp's solution

to RNA Transcription in the Java Track

Published at Jul 13 2018 · 0 comments
Test suite


This solution was written on an old version of Exercism. The tests below might not correspond to the solution code, and the exercise may have changed since this code was written.

Given a DNA strand, return its RNA complement (per RNA transcription).

Both DNA and RNA strands are a sequence of nucleotides.

The four nucleotides found in DNA are adenine (A), cytosine (C), guanine (G) and thymine (T).

The four nucleotides found in RNA are adenine (A), cytosine (C), guanine (G) and uracil (U).

Given a DNA strand, its transcribed RNA strand is formed by replacing each nucleotide with its complement:

  • G -> C
  • C -> G
  • T -> A
  • A -> U

Java Tips

For more help on how to solve this exercise, please refer to the tutorial provided as part of the hello world exercise: TUTORIAL.md

Running the tests

You can run all the tests for an exercise by entering

$ gradle test

in your terminal.


Hyperphysics http://hyperphysics.phy-astr.gsu.edu/hbase/Organic/transcription.html

Submitting Incomplete Solutions

It's possible to submit an incomplete solution so you can see how others have completed the exercise.


import org.junit.Before;
import org.junit.Ignore;
import org.junit.Test;

import static org.junit.Assert.assertEquals;

public class RnaTranscriptionTest {

    private RnaTranscription rnaTranscription;

    public void setUp() {
        rnaTranscription = new RnaTranscription();

    public void testRnaTranscriptionOfCytosineIsGuanine() {
        assertEquals("G", rnaTranscription.transcribe("C"));

    @Ignore("Remove to run test")
    public void testRnaTranscriptionOfGuanineIsCytosine() {
        assertEquals("C", rnaTranscription.transcribe("G"));

    @Ignore("Remove to run test")
    public void testRnaTranscriptionOfThymineIsAdenine() {
        assertEquals("A", rnaTranscription.transcribe("T"));

    @Ignore("Remove to run test")
    public void testRnaTranscriptionOfAdenineIsUracil() {
        assertEquals("U", rnaTranscription.transcribe("A"));

    @Ignore("Remove to run test")
    public void testRnaTranscription() {
        assertEquals("UGCACCAGAAUU", rnaTranscription.transcribe("ACGTGGTCTTAA"));

import java.util.Map;
import java.util.HashMap;

public class RnaTranscription {

  private static final Map<Character, Character> RNA_PAIRS = new HashMap<Character, Character>(){{
        put('C', 'G');
        put('G', 'C');
        put('T', 'A');
        put('A', 'U');

  public static String ofDna(String input) {

    String result = "";

    for(char c : input.toCharArray()) {
      result += RNA_PAIRS.get(c);

    return result;



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