Resolving kata most frequent item in a collection.

src/main/java/org/fundacionjala/coding/jose/FrequentItem.java

@@ -0,0 +1,29 @@
+package org.fundacionjala.coding.jose;
+
+/**
+ * Created by JoseTorrez on 9/5/2017.
+ */
+public class FrequentItem {
+
+    /**
+     * This method is for find the most frequent number in a collection.
+     * @param collection of numbers received.
+     * @return the item most repeated in the collection.
+     */
+    public int mostFrequentItemCount(int[] collection) {
+        int most = 0;
+        for (int i = 0; i < collection.length; i++) {
+            int count = 0;
+            for (int x : collection) {
+                if (x == collection[i]) {
+                    count++;
+                }
+            }
+            if (count > most) {
+                most = count;
+            }
+        }
+        return most;
+    }
+
+}

src/test/java/org/fundacionjala/coding/jose/FrequentItemTest.java

@@ -0,0 +1,89 @@
+package org.fundacionjala.coding.jose;
+
+import java.util.Arrays;
+import java.util.Random;
+
+import org.junit.Before;
+import org.junit.Test;
+
+import static org.junit.Assert.assertEquals;
+
+/**
+ * Created by JoseTorrez on 9/5/2017.
+ */
+public class FrequentItemTest {
+    private FrequentItem frequentItem;
+
+    /**
+     * Initializator.
+     */
+    @Before
+    public void setUp() {
+        frequentItem = new FrequentItem();
+
+    }
+
+    /**
+     * Basic Test.
+     */
+    @Test
+    public void basicTests() {
+        String msg = "Should work with example test cases";
+        assertEquals(msg, 2, frequentItem.mostFrequentItemCount(new int[]{3, -1, -1}));
+        assertEquals(msg, 5,
+                frequentItem.mostFrequentItemCount(new int[]{3, -1, -1, -1, 2, 3, -1, 3, -1, 2, 4, 9, 3}));
+    }
+
+    /**
+     * Edge Test.
+     */
+    @Test
+    public void edgeTests() {
+        assertEquals("Should work for empty arrays", 0,
+                frequentItem.mostFrequentItemCount(new int[0]));
+        assertEquals("Should work for 1-element arrays", 1,
+                frequentItem.mostFrequentItemCount(new int[]{9}));
+        assertEquals("Should work with multiple most frequent items, e.g. nine 7's and nine 1's", 3,
+                frequentItem.mostFrequentItemCount(new int[]{7, 1, 7, 1, 7, 1}));
+    }
+
+    /**
+     * Test for numbers generated by random.
+     */
+    @Test
+    public void randomTests() {
+        Random randGen = new Random();
+        System.out.println("Testing 40 random arrays...");
+        for (int i = 0; i < 40; i++) {
+            int[] testArr = new int[randGen.nextInt(30)];
+            for (int e = 0; e < testArr.length; e++) {
+                testArr[e] = randGen.nextInt(30) - 15;
+            }
+            assertEquals(mostFrequentAns(testArr),
+                    frequentItem.mostFrequentItemCount(testArr));
+        }
+    }
+
+    /**
+     * @param collection Integer.
+     * @return Integer.
+     */
+    private int mostFrequentAns(int[] collection) {
+        int max = 0;
+        int currMax = 0;
+        int currNum = 0;
+        Arrays.sort(collection);
+        for (int i = 0; i < collection.length; i++) {
+            if (currNum != collection[i]) {
+                if (currMax > max) {
+                    max = currMax;
+                }
+                currMax = 1;
+                currNum = collection[i];
+            } else {
+                currMax++;
+            }
+        }
+        return (currMax > max ? currMax : max);
+    }
+}