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Add tests, remove main in IterativeTernarySearch (#5668)
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@ -1,22 +1,26 @@
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package com.thealgorithms.searches;
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import com.thealgorithms.devutils.searches.SearchAlgorithm;
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import java.util.Arrays;
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import java.util.Random;
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import java.util.stream.Stream;
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/**
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* A iterative version of a ternary search algorithm This is better way to
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* implement the ternary search, because a recursive version adds some overhead
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* to a stack. But in java the compile can transform the recursive version to
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* iterative implicitly, so there are no much differences between these two
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* algorithms
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* An iterative implementation of the Ternary Search algorithm.
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*
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* <p>
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* Worst-case performance Θ(log3(N)) Best-case performance O(1) Average
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* performance Θ(log3(N)) Worst-case space complexity O(1)
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* Ternary search is a divide-and-conquer algorithm that splits the array into three parts
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* instead of two, as in binary search. This implementation is iterative, reducing the overhead
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* associated with recursive function calls. However, the recursive version can also be optimized
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* by the Java compiler to resemble the iterative version, resulting in similar performance.
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*
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* <p>
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* Worst-case performance: Θ(log3(N))<br>
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* Best-case performance: O(1)<br>
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* Average performance: Θ(log3(N))<br>
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* Worst-case space complexity: O(1)
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*
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* <p>
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* This class implements the {@link SearchAlgorithm} interface, providing a generic search method
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* for any comparable type.
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*
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* @author Podshivalov Nikita (https://github.com/nikitap492)
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* @see SearchAlgorithm
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* @see TernarySearch
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* @since 2018-04-13
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@ -25,6 +29,13 @@ public class IterativeTernarySearch implements SearchAlgorithm {
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@Override
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public <T extends Comparable<T>> int find(T[] array, T key) {
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if (array == null || array.length == 0 || key == null) {
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return -1;
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}
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if (array.length == 1) {
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return array[0].compareTo(key) == 0 ? 0 : -1;
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}
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int left = 0;
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int right = array.length - 1;
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@ -50,23 +61,4 @@ public class IterativeTernarySearch implements SearchAlgorithm {
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return -1;
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}
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public static void main(String[] args) {
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// just generate data
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Random r = new Random();
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int size = 100;
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int maxElement = 100000;
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Integer[] integers = Stream.generate(() -> r.nextInt(maxElement)).limit(size).sorted().toArray(Integer[] ::new);
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// the element that should be found
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Integer shouldBeFound = integers[r.nextInt(size - 1)];
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IterativeTernarySearch search = new IterativeTernarySearch();
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int atIndex = search.find(integers, shouldBeFound);
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System.out.printf("Should be found: %d. Found %d at index %d. An array length %d%n", shouldBeFound, integers[atIndex], atIndex, size);
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int toCheck = Arrays.binarySearch(integers, shouldBeFound);
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System.out.printf("Found by system method at an index: %d. Is equal: %b%n", toCheck, toCheck == atIndex);
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}
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}
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