BAEL-1297 Find kth largest element in a sequence of numbers (#3332)

* Example Code For Evaluation Article This is an example code for the evaluation article on "Different Types of Bean Injection in Spring" * Added unit tests * Minor changes to application context * Removed code committed for evaluation article * BAEL-944 Demonstrating the problems with new Url pattern matching in Spring 5 * BAEL-944 Demonstrating the problems with new Url pattern matching in Spring 5 * BAEL-944 Exploring the Spring MVC URL Matching Improvements * BAEL-944 Exploring the Spring MVC URL Matching Improvements * BAEL-944 Exploring the Spring MVC URL Matching Improvements * BAEL-944 Code Formatting and solving build issue * BAEL-944 Resolving build issue due to change in Spring version * BAEL-944 Resolving build issue * BAEL-944 Formatting code * BAEL-944 Moving tests to correct package * BAEL-944 Moving tests to correct package * BAEL-944 Replacing @RequestMapping by @GetMapping * BAEL-944 Remove unnecessary attribute name, "value" in annotations * BAEL-79 Intro to Activiti with Spring * BAEL-79 Intro to Activiti with Spring * BAEL-79 Adding activiti module to the parent modules * BAEL-79 Using latest version * BAEL-79 Update Spring boot version that works with Activiti * BAEL-79 Replace RequestMapping with GetMapping * BAEL-79 Use Java 8 Syntax * BAEL-79 Formatting * BAEL-79 changed module name * BAEL-378 A Guide to Activiti with Java * BAEL-79 Fixed unit tests * BAEL-79 Simplified the process * BAEL-79 Fix test cases * BAEL-1045 Lambda Behave * BAEL-1045 Lambda Behave * BAEL-1045 Lambda Behave * BAEL-1090 Difference between compact and compressed strings in Java 9 * BAEL-1237 String Formatter * BAEL-1237 String Formatter * BAEL-1237 String Formatter * BAEL-1237 String Formatter * BAEL-1237 Guide to java.util.Formatter * BAEL-1297 Find kth largest element in a sequence of numbers * BAEL-1297 fixed issues and modified file name * BAEL-1297 Modified randomized quickselect * BAEL-1297 added additional sorting method * BAEL-1297 UnitTest fix * BAEL-1297 Additional method Added QuickSelect With Iterative Partition method * BAEL-1297 Added AssertJ annotations * BAEL-1297 added missing assertj dependancy
2018-01-06 08:08:02 +05:30
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+package com.baeldung.algorithms.kthlargest;
+
+import static org.assertj.core.api.Assertions.*;
+
+import org.junit.Before;
+import org.junit.Test;
+
+public class FindKthLargestUnitTest {
+
+    private FindKthLargest findKthLargest;
+    private Integer[] arr = { 3, 7, 1, 2, 8, 10, 4, 5, 6, 9 };
+
+    @Before
+    public void setup() {
+        findKthLargest = new FindKthLargest();
+    }
+
+    @Test
+    public void givenIntArray_whenFindKthLargestBySorting_thenGetResult() {
+        int k = 3;
+        assertThat(findKthLargest.findKthLargestBySorting(arr, k)).isEqualTo(8);
+    }
+
+    @Test
+    public void givenIntArray_whenFindKthLargestBySortingDesc_thenGetResult() {
+        int k = 3;
+        assertThat(findKthLargest.findKthLargestBySortingDesc(arr, k)).isEqualTo(8);
+    }
+
+    @Test
+    public void givenIntArray_whenFindKthLargestByQuickSelect_thenGetResult() {
+        int k = 3;
+        int kthLargest = arr.length - k;
+        assertThat(findKthLargest.findKthElementByQuickSelect(arr, 0, arr.length - 1, kthLargest)).isEqualTo(8);
+    }
+
+    @Test
+    public void givenIntArray_whenFindKthElementByQuickSelectIterative_thenGetResult() {
+        int k = 3;
+        int kthLargest = arr.length - k;
+        assertThat(findKthLargest.findKthElementByQuickSelectWithIterativePartition(arr, 0, arr.length - 1, kthLargest)).isEqualTo(8);
+    }
+
+    @Test
+    public void givenIntArray_whenFindKthSmallestByQuickSelect_thenGetResult() {
+        int k = 3;
+        assertThat(findKthLargest.findKthElementByQuickSelect(arr, 0, arr.length - 1, k - 1)).isEqualTo(3);
+    }
+
+    @Test
+    public void givenIntArray_whenFindKthLargestByRandomizedQuickSelect_thenGetResult() {
+        int k = 3;
+        int kthLargest = arr.length - k;
+        assertThat(findKthLargest.findKthElementByRandomizedQuickSelect(arr, 0, arr.length - 1, kthLargest)).isEqualTo(8);
+    }
+
+}