From edcfcaece29b37226f4eb0966f9b054dc10b8203 Mon Sep 17 00:00:00 2001 From: Hardik Pawar Date: Mon, 14 Oct 2024 15:32:06 +0530 Subject: [PATCH 1/4] feat: Add `OptimalFileMerging` new algorithm with Junit tests --- .../greedyalgorithms/OptimalFileMerging.java | 47 +++++++++++++++++++ .../OptimalFileMergingTest.java | 22 +++++++++ 2 files changed, 69 insertions(+) create mode 100644 src/main/java/com/thealgorithms/greedyalgorithms/OptimalFileMerging.java create mode 100644 src/test/java/com/thealgorithms/greedyalgorithms/OptimalFileMergingTest.java diff --git a/src/main/java/com/thealgorithms/greedyalgorithms/OptimalFileMerging.java b/src/main/java/com/thealgorithms/greedyalgorithms/OptimalFileMerging.java new file mode 100644 index 000000000000..533faffa94de --- /dev/null +++ b/src/main/java/com/thealgorithms/greedyalgorithms/OptimalFileMerging.java @@ -0,0 +1,47 @@ +package com.thealgorithms.greedyalgorithms; + +import java.util.PriorityQueue; + +/** + * Class to solve the Optimal File Merging Problem. + * The goal is to minimize the cost of merging files, where the cost of merging two files is the sum of their sizes. + * The cost of merging all files is the sum of the costs of merging each pair of files. + * Example: + * files = [4, 3, 2, 6] + * The minimum cost to merge all files is 29. + * Steps: + * 1. Merge files 2 and 3 (cost = 2 + 3 = 5). New files = [4, 5, 6] + * 2. Merge files 4 and 5 (cost = 4 + 5 = 9). New files = [6, 9] + * 3. Merge files 6 and 9 (cost = 6 + 9 = 15). New files = [15] + * Total cost = 5 + 9 + 15 = 29 + * + * @author Hardvan + */ +public final class OptimalFileMerging { + private OptimalFileMerging() { + } + + /** + * Calculates the minimum cost to merge all files. + * + * @param files array of file sizes + * @return the minimum cost to merge the files + */ + public static int minMergeCost(int[] files) { + PriorityQueue minHeap = new PriorityQueue<>(); + for (int file : files) { + minHeap.add(file); + } + + int totalCost = 0; + while (minHeap.size() > 1) { + int first = minHeap.poll(); + int second = minHeap.poll(); + int cost = first + second; + totalCost += cost; + + minHeap.add(cost); + } + return totalCost; + } +} diff --git a/src/test/java/com/thealgorithms/greedyalgorithms/OptimalFileMergingTest.java b/src/test/java/com/thealgorithms/greedyalgorithms/OptimalFileMergingTest.java new file mode 100644 index 000000000000..9ff2b95ff2e5 --- /dev/null +++ b/src/test/java/com/thealgorithms/greedyalgorithms/OptimalFileMergingTest.java @@ -0,0 +1,22 @@ +package com.thealgorithms.greedyalgorithms; + +import static org.junit.jupiter.api.Assertions.assertEquals; + +import java.util.stream.Stream; +import org.junit.jupiter.params.ParameterizedTest; +import org.junit.jupiter.params.provider.Arguments; +import org.junit.jupiter.params.provider.MethodSource; + +public class OptimalFileMergingTest { + + @ParameterizedTest + @MethodSource("fileMergingProvider") + public void testMinMergeCost(int[] files, int expected) { + assertEquals(expected, OptimalFileMerging.minMergeCost(files)); + } + + private static Stream fileMergingProvider() { + return Stream.of(Arguments.of(new int[] {4, 3, 2, 6}, 29), Arguments.of(new int[] {5}, 0), Arguments.of(new int[] {2, 2, 2}, 10), Arguments.of(new int[] {10, 5, 3, 2}, 35), Arguments.of(new int[] {1, 1, 1, 1}, 8), Arguments.of(new int[] {1, 2, 3, 4, 5}, 33), + Arguments.of(new int[] {1, 2, 3, 4, 5, 6}, 51), Arguments.of(new int[] {1, 2, 3, 4, 5, 6, 7}, 74), Arguments.of(new int[] {1, 2, 3, 4, 5, 6, 7, 8}, 102), Arguments.of(new int[] {1, 2, 3, 4, 5, 6, 7, 8, 9}, 135)); + } +} From 9a83d71a84728c37b35d21fbbe75bee3a0200838 Mon Sep 17 00:00:00 2001 From: Hardvan Date: Mon, 14 Oct 2024 10:02:25 +0000 Subject: [PATCH 2/4] Update directory --- DIRECTORY.md | 2 ++ 1 file changed, 2 insertions(+) diff --git a/DIRECTORY.md b/DIRECTORY.md index f354913a05e8..3a27fbdff95b 100644 --- a/DIRECTORY.md +++ b/DIRECTORY.md @@ -315,6 +315,7 @@ * [JobSequencing](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/greedyalgorithms/JobSequencing.java) * [MergeIntervals](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/greedyalgorithms/MergeIntervals.java) * [MinimizingLateness](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/greedyalgorithms/MinimizingLateness.java) + * [OptimalFileMerging](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/greedyalgorithms/OptimalFileMerging.java) * io * [BufferedReader](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/io/BufferedReader.java) * lineclipping @@ -907,6 +908,7 @@ * [JobSequencingTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/greedyalgorithms/JobSequencingTest.java) * [MergeIntervalsTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/greedyalgorithms/MergeIntervalsTest.java) * [MinimizingLatenessTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/greedyalgorithms/MinimizingLatenessTest.java) + * [OptimalFileMergingTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/greedyalgorithms/OptimalFileMergingTest.java) * io * [BufferedReaderTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/io/BufferedReaderTest.java) * lineclipping From 609c4b4cfee811bd53bd65fe2876a65fe127385e Mon Sep 17 00:00:00 2001 From: Hardik Pawar Date: Mon, 14 Oct 2024 15:46:51 +0530 Subject: [PATCH 3/4] Fix --- .../thealgorithms/greedyalgorithms/OptimalFileMerging.java | 5 +++++ 1 file changed, 5 insertions(+) diff --git a/src/main/java/com/thealgorithms/greedyalgorithms/OptimalFileMerging.java b/src/main/java/com/thealgorithms/greedyalgorithms/OptimalFileMerging.java index 533faffa94de..7a1f2edf8180 100644 --- a/src/main/java/com/thealgorithms/greedyalgorithms/OptimalFileMerging.java +++ b/src/main/java/com/thealgorithms/greedyalgorithms/OptimalFileMerging.java @@ -23,6 +23,11 @@ private OptimalFileMerging() { /** * Calculates the minimum cost to merge all files. + * Steps: + * 1. Add all files to a min heap. + * 2. Remove the two smallest files from the heap, merge them, and add the result back to the heap. + * 3. Repeat step 2 until there is only one file left in the heap. + * 4. The total cost is the sum of all the costs of merging the files. * * @param files array of file sizes * @return the minimum cost to merge the files From 2101096b0046b21173d2b4a3a1ee1d5aa7455775 Mon Sep 17 00:00:00 2001 From: siriak Date: Fri, 25 Oct 2024 20:32:51 +0000 Subject: [PATCH 4/4] Update directory --- DIRECTORY.md | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-) diff --git a/DIRECTORY.md b/DIRECTORY.md index bf7e868a1a1c..25b8fc2ff40d 100644 --- a/DIRECTORY.md +++ b/DIRECTORY.md @@ -327,8 +327,8 @@ * [JobSequencing](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/greedyalgorithms/JobSequencing.java) * [MergeIntervals](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/greedyalgorithms/MergeIntervals.java) * [MinimizingLateness](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/greedyalgorithms/MinimizingLateness.java) - * [OptimalFileMerging](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/greedyalgorithms/OptimalFileMerging.java) * [MinimumWaitingTime](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/greedyalgorithms/MinimumWaitingTime.java) + * [OptimalFileMerging](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/greedyalgorithms/OptimalFileMerging.java) * [StockProfitCalculator](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/greedyalgorithms/StockProfitCalculator.java) * io * [BufferedReader](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/io/BufferedReader.java) @@ -572,6 +572,7 @@ * [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 + * [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) * sorts * [AdaptiveMergeSort](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/sorts/AdaptiveMergeSort.java) @@ -954,8 +955,8 @@ * [JobSequencingTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/greedyalgorithms/JobSequencingTest.java) * [MergeIntervalsTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/greedyalgorithms/MergeIntervalsTest.java) * [MinimizingLatenessTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/greedyalgorithms/MinimizingLatenessTest.java) - * [OptimalFileMergingTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/greedyalgorithms/OptimalFileMergingTest.java) * [MinimumWaitingTimeTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/greedyalgorithms/MinimumWaitingTimeTest.java) + * [OptimalFileMergingTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/greedyalgorithms/OptimalFileMergingTest.java) * [StockProfitCalculatorTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/greedyalgorithms/StockProfitCalculatorTest.java) * io * [BufferedReaderTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/io/BufferedReaderTest.java) @@ -1165,6 +1166,7 @@ * [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 + * [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) * sorts * [AdaptiveMergeSortTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/sorts/AdaptiveMergeSortTest.java)