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Implement practice exercise square-root (exercism#2362)
* Add empty exercise structure * Add tests and stub implementation * Add reference implementation * Steer students away from `Math.sqrt` * Increase difficulty * Revert changes to exercises/build.gradle This is being fixed in exercism#2363 instead.
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‎config.json‎

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"practices": ["lists", "classes", "for-loops"],
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"prerequisites" :["lists"],
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"difficulty": 2
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},
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{
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"slug": "square-root",
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"name": "Square Root",
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"uuid": "61886554-ec84-422a-bbf9-aeee37c45bb6",
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"practices": ["numbers"],
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"prerequisites": ["numbers"],
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"difficulty": 5
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}
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],
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"foregone": []

‎exercises/practice/square-root/.docs/instructions.append.md‎

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# Instructions (appended)
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The goal of this exercise is to practice working with numbers, so stay away
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from `java.lang.Math`!

‎exercises/practice/square-root/.docs/instructions.md‎

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# Instructions
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Given a natural radicand, return its square root.
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Note that the term "radicand" refers to the number for which the root is to be determined.
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That is, it is the number under the root symbol.
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Check out the Wikipedia pages on [square root][square-root] and [methods of computing square roots][computing-square-roots].
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Recall also that natural numbers are positive real whole numbers (i.e. 1, 2, 3 and up).
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[square-root]: https://en.wikipedia.org/wiki/Square_root
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[computing-square-roots]: https://en.wikipedia.org/wiki/Methods_of_computing_square_roots

‎exercises/practice/square-root/.meta/config.json‎

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{
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"authors": ["sanderploegsma"],
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"contributors": [],
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"files": {
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"solution": ["src/main/java/SquareRoot.java"],
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"test": ["src/test/java/SquareRootTest.java"],
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"example": [".meta/src/reference/java/SquareRoot.java"],
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"invalidator": ["build.gradle"]
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},
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"blurb": "Given a natural radicand, return its square root.",
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"source": "wolf99",
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"source_url": "https://github.com/exercism/problem-specifications/pull/1582"
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}

‎exercises/practice/square-root/.meta/src/reference/java/SquareRoot.java‎

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public class SquareRoot {
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/**
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* Finds the square root of the given radicand using digit-by-digit calculation.
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*
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* @param radicand a natural number
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* @return square root of the given radicand
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* @see <a href="https://en.wikipedia.org/wiki/Methods_of_computing_square_roots#Binary_numeral_system_(base_2)">
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* Source on Wikipedia
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* </a>
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*/
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public int squareRoot(int radicand) {
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int x = radicand;
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int c = 0;
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int d = 1 << 30;
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while (d > radicand) {
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d >>= 2;
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}
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while (d != 0) {
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if (x >= c + d) {
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x -= c + d;
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c = (c >> 1) + d;
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} else {
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c >>= 1;
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}
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d >>= 2;
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}
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return c;
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}
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}

‎exercises/practice/square-root/.meta/tests.toml‎

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# This is an auto-generated file.
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#
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# Regenerating this file via `configlet sync` will:
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# - Recreate every `description` key/value pair
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# - Recreate every `reimplements` key/value pair, where they exist in problem-specifications
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# - Remove any `include = true` key/value pair (an omitted `include` key implies inclusion)
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# - Preserve any other key/value pair
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#
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# As user-added comments (using the # character) will be removed when this file
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# is regenerated, comments can be added via a `comment` key.
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[9b748478-7b0a-490c-b87a-609dacf631fd]
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description = "root of 1"
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[7d3aa9ba-9ac6-4e93-a18b-2e8b477139bb]
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description = "root of 4"
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[6624aabf-3659-4ae0-a1c8-25ae7f33c6ef]
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description = "root of 25"
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[93beac69-265e-4429-abb1-94506b431f81]
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description = "root of 81"
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[fbddfeda-8c4f-4bc4-87ca-6991af35360e]
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description = "root of 196"
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[c03d0532-8368-4734-a8e0-f96a9eb7fc1d]
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description = "root of 65025"

‎exercises/practice/square-root/.meta/version‎

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1.0.0

‎exercises/practice/square-root/build.gradle‎

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plugins {
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id "java"
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}
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repositories {
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mavenCentral()
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}
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dependencies {
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testImplementation platform("org.junit:junit-bom:5.10.0")
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testImplementation "org.junit.jupiter:junit-jupiter"
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testImplementation "org.assertj:assertj-core:3.15.0"
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}
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test {
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useJUnitPlatform()
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testLogging {
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exceptionFormat = "full"
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showStandardStreams = true
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events = ["passed", "failed", "skipped"]
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}
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}

‎exercises/practice/square-root/src/main/java/SquareRoot.java‎

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public class SquareRoot {
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public int squareRoot(int radicand) {
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throw new UnsupportedOperationException("Please implement the SquareRoot.squareRoot method.");
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}
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}

‎exercises/practice/square-root/src/test/java/SquareRootTest.java‎

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import org.junit.jupiter.api.Disabled;
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import org.junit.jupiter.api.DisplayName;
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import org.junit.jupiter.api.Test;
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import static org.assertj.core.api.Assertions.assertThat;
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public class SquareRootTest {
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@Test
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@DisplayName("Square root of 1")
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public void squareRootOf1() {
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assertThat(new SquareRoot().squareRoot(1))
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.isEqualTo(1);
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}
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@Disabled("Remove to run test")
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@Test
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@DisplayName("Square root of 4")
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public void squareRootOf4() {
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assertThat(new SquareRoot().squareRoot(4))
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.isEqualTo(2);
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}
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@Disabled("Remove to run test")
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@Test
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@DisplayName("Square root of 25")
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public void squareRootOf25() {
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assertThat(new SquareRoot().squareRoot(25))
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.isEqualTo(5);
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}
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@Disabled("Remove to run test")
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@Test
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@DisplayName("Square root of 81")
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public void squareRootOf81() {
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assertThat(new SquareRoot().squareRoot(81))
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.isEqualTo(9);
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}
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@Disabled("Remove to run test")
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@Test
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@DisplayName("Square root of 196")
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public void squareRootOf196() {
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assertThat(new SquareRoot().squareRoot(196))
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.isEqualTo(14);
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}
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@Disabled("Remove to run test")
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@Test
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@DisplayName("Square root of 65025")
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public void squareRootOf65025() {
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assertThat(new SquareRoot().squareRoot(65025))
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.isEqualTo(255);
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}
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}

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