diff --git a/DIRECTORY.md b/DIRECTORY.md index 0c9aeca4e59a..e34b9eba1247 100644 --- a/DIRECTORY.md +++ b/DIRECTORY.md @@ -466,6 +466,7 @@ * [SumWithoutArithmeticOperators](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/maths/SumWithoutArithmeticOperators.java) * [TrinomialTriangle](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/maths/TrinomialTriangle.java) * [TwinPrime](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/maths/TwinPrime.java) + * [UniformNumbers](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/maths/UniformNumbers.java) * [VampireNumber](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/maths/VampireNumber.java) * [VectorCrossProduct](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/maths/VectorCrossProduct.java) * [Volume](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/maths/Volume.java) @@ -597,6 +598,7 @@ * [UnionFind](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/searches/UnionFind.java) * [UpperBound](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/searches/UpperBound.java) * slidingwindow + * [LongestSubarrayWithSumLessOrEqualToK](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/slidingwindow/LongestSubarrayWithSumLessOrEqualToK.java) * [LongestSubstringWithoutRepeatingCharacters](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/slidingwindow/LongestSubstringWithoutRepeatingCharacters.java) * [MaxSumKSizeSubarray](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/slidingwindow/MaxSumKSizeSubarray.java) * [MinSumKSizeSubarray](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/slidingwindow/MinSumKSizeSubarray.java) @@ -1119,6 +1121,7 @@ * [SumWithoutArithmeticOperatorsTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/maths/SumWithoutArithmeticOperatorsTest.java) * [TestArmstrong](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/maths/TestArmstrong.java) * [TwinPrimeTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/maths/TwinPrimeTest.java) + * [UniformNumbersTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/maths/UniformNumbersTest.java) * [VolumeTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/maths/VolumeTest.java) * misc * [ColorContrastRatioTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/misc/ColorContrastRatioTest.java) @@ -1228,6 +1231,7 @@ * [UnionFindTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/searches/UnionFindTest.java) * [UpperBoundTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/searches/UpperBoundTest.java) * slidingwindow + * [LongestSubarrayWithSumLessOrEqualToKTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/slidingwindow/LongestSubarrayWithSumLessOrEqualToKTest.java) * [LongestSubstringWithoutRepeatingCharactersTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/slidingwindow/LongestSubstringWithoutRepeatingCharactersTest.java) * [MaxSumKSizeSubarrayTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/slidingwindow/MaxSumKSizeSubarrayTest.java) * [MinSumKSizeSubarrayTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/slidingwindow/MinSumKSizeSubarrayTest.java) diff --git a/src/main/java/com/thealgorithms/maths/UniformNumbers.java b/src/main/java/com/thealgorithms/maths/UniformNumbers.java new file mode 100644 index 000000000000..c83783aab0b3 --- /dev/null +++ b/src/main/java/com/thealgorithms/maths/UniformNumbers.java @@ -0,0 +1,50 @@ +package com.thealgorithms.maths; + +/** + * A positive integer is considered uniform if all + * of its digits are equal. For example, 222 is uniform, + * while 223 is not. + * Given two positive integers a and b, determine the + * number of uniform integers between a and b. + */ +public final class UniformNumbers { + // Private constructor to prevent instantiation of the utility class + private UniformNumbers() { + // Prevent instantiation + } + /** + * This function will find the number of uniform numbers + * from 1 to num + * @param num upper limit to find the uniform numbers + * @return the count of uniform numbers between 1 and num + */ + public static int uniformNumbers(int num) { + String numStr = Integer.toString(num); + int uniformCount = (numStr.length() - 1) * 9; + int finalUniform = Integer.parseInt(String.valueOf(numStr.charAt(0)).repeat(numStr.length())); + + if (finalUniform <= num) { + uniformCount += Integer.parseInt(String.valueOf(numStr.charAt(0))); + } else { + uniformCount += Integer.parseInt(String.valueOf(numStr.charAt(0))) - 1; + } + + return uniformCount; + } + /** + * This function will calculate the number of uniform numbers + * between a and b + * @param a lower bound of range + * @param b upper bound of range + * @return the count of uniform numbers between a and b + */ + public static int countUniformIntegers(int a, int b) { + if (b > a && b > 0 && a > 0) { + return uniformNumbers(b) - uniformNumbers(a - 1); + } else if (b == a) { + return 1; + } else { + return 0; + } + } +} diff --git a/src/test/java/com/thealgorithms/maths/UniformNumbersTest.java b/src/test/java/com/thealgorithms/maths/UniformNumbersTest.java new file mode 100644 index 000000000000..ac46c00014ad --- /dev/null +++ b/src/test/java/com/thealgorithms/maths/UniformNumbersTest.java @@ -0,0 +1,56 @@ +package com.thealgorithms.maths; + +import static org.junit.jupiter.api.Assertions.assertEquals; + +import org.junit.jupiter.api.Test; + +class UniformNumbersTest { + + @Test + void testSingleUniformDigitRange() { + assertEquals(1, UniformNumbers.countUniformIntegers(1, 1)); + assertEquals(9, UniformNumbers.countUniformIntegers(1, 9)); + } + + @Test + void testSmallRange() { + assertEquals(1, UniformNumbers.countUniformIntegers(10, 11)); + assertEquals(2, UniformNumbers.countUniformIntegers(22, 33)); + } + + @Test + void testRangeWithNoUniformNumbers() { + assertEquals(0, UniformNumbers.countUniformIntegers(12, 21)); + assertEquals(0, UniformNumbers.countUniformIntegers(123, 128)); + } + + @Test + void testRangeWithAllUniformNumbers() { + assertEquals(9, UniformNumbers.countUniformIntegers(1, 9)); + assertEquals(18, UniformNumbers.countUniformIntegers(1, 99)); + } + + @Test + void testMultiDigitRangeWithUniformNumbers() { + assertEquals(1, UniformNumbers.countUniformIntegers(100, 111)); + assertEquals(2, UniformNumbers.countUniformIntegers(111, 222)); + } + + @Test + void testExactUniformBoundary() { + assertEquals(1, UniformNumbers.countUniformIntegers(111, 111)); + assertEquals(2, UniformNumbers.countUniformIntegers(111, 222)); + } + + @Test + void testLargeRange() { + assertEquals(27, UniformNumbers.countUniformIntegers(1, 999)); + assertEquals(36, UniformNumbers.countUniformIntegers(1, 9999)); + } + + @Test + void testInvalidRange() { + assertEquals(0, UniformNumbers.countUniformIntegers(500, 100)); + assertEquals(0, UniformNumbers.countUniformIntegers(-100, -1)); + } +}