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Cleanup SumOfDigits and its tests (#4994)

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This commit is contained in:
Piotr Idzik
2024-01-05 22:05:52 +01:00
committed by GitHub
parent 1ea95ffa92
commit 8930ab5b16
2 changed files with 32 additions and 45 deletions
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35
src/main/java/com/thealgorithms/maths/SumOfDigits.java
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@ -1,13 +1,7 @@
package com.thealgorithms.maths;
public class SumOfDigits {
public static void main(String[] args) {
assert sumOfDigits(-123) == 6 && sumOfDigitsRecursion(-123) == 6 && sumOfDigitsFast(-123) == 6;
assert sumOfDigits(0) == 0 && sumOfDigitsRecursion(0) == 0 && sumOfDigitsFast(0) == 0;
assert sumOfDigits(12345) == 15 && sumOfDigitsRecursion(12345) == 15 && sumOfDigitsFast(12345) == 15;
public final class SumOfDigits {
private SumOfDigits() {
}
/**
@ -17,12 +11,12 @@ public class SumOfDigits {
* @return sum of digits of given {@code number}
*/
public static int sumOfDigits(int number) {
number = number < 0 ? -number : number;
/* calculate abs value */
final int base = 10;
number = Math.abs(number);
int sum = 0;
while (number != 0) {
sum += number % 10;
number /= 10;
sum += number % base;
number /= base;
}
return sum;
}
@ -34,9 +28,9 @@ public class SumOfDigits {
* @return sum of digits of given {@code number}
*/
public static int sumOfDigitsRecursion(int number) {
number = number < 0 ? -number : number;
/* calculate abs value */
return number < 10 ? number : number % 10 + sumOfDigitsRecursion(number / 10);
final int base = 10;
number = Math.abs(number);
return number < base ? number : number % base + sumOfDigitsRecursion(number / base);
}
/**
@ -45,14 +39,7 @@ public class SumOfDigits {
* @param number the number contains digits
* @return sum of digits of given {@code number}
*/
public static int sumOfDigitsFast(int number) {
number = number < 0 ? -number : number;
/* calculate abs value */
char[] digits = (number + "").toCharArray();
int sum = 0;
for (int i = 0; i < digits.length; ++i) {
sum += digits[i] - '0';
}
return sum;
public static int sumOfDigitsFast(final int number) {
return String.valueOf(Math.abs(number)).chars().map(c -> c - '0').reduce(0, Integer::sum);
}
}

42
src/test/java/com/thealgorithms/maths/SumOfDigitsTest.java
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@ -1,31 +1,31 @@
package com.thealgorithms.maths;
import static org.junit.jupiter.api.Assertions.*;
import org.junit.jupiter.api.Test;
import java.util.stream.Stream;
import org.junit.jupiter.api.Assertions;
import org.junit.jupiter.params.ParameterizedTest;
import org.junit.jupiter.params.provider.Arguments;
import org.junit.jupiter.params.provider.MethodSource;
class SumOfDigitsTest {
SumOfDigits SoD = new SumOfDigits();
@Test
void testZero() {
assertEquals(0, SumOfDigits.sumOfDigits(0));
assertEquals(0, SumOfDigits.sumOfDigitsRecursion(0));
assertEquals(0, SumOfDigits.sumOfDigitsFast(0));
@ParameterizedTest
@MethodSource("testCases")
void sumOfDigitsTest(final int expected, final int input) {
Assertions.assertEquals(expected, SumOfDigits.sumOfDigits(input));
}
@Test
void testPositive() {
assertEquals(15, SumOfDigits.sumOfDigits(12345));
assertEquals(15, SumOfDigits.sumOfDigitsRecursion(12345));
assertEquals(15, SumOfDigits.sumOfDigitsFast(12345));
@ParameterizedTest
@MethodSource("testCases")
void sumOfDigitsRecursionTest(final int expected, final int input) {
Assertions.assertEquals(expected, SumOfDigits.sumOfDigitsRecursion(input));
}
@Test
void testNegative() {
assertEquals(6, SumOfDigits.sumOfDigits(-123));
assertEquals(6, SumOfDigits.sumOfDigitsRecursion(-123));
assertEquals(6, SumOfDigits.sumOfDigitsFast(-123));
@ParameterizedTest
@MethodSource("testCases")
void sumOfDigitsFastTest(final int expected, final int input) {
Assertions.assertEquals(expected, SumOfDigits.sumOfDigitsFast(input));
}
private static Stream<Arguments> testCases() {
return Stream.of(Arguments.of(0, 0), Arguments.of(1, 1), Arguments.of(15, 12345), Arguments.of(6, -123), Arguments.of(1, -100000), Arguments.of(8, 512));
}
}