done (naive approach)

Author: Ram swaroop

src/me/ramswaroop/arrays/MaxInAllSubArrays.java

@@ -0,0 +1,46 @@
+package me.ramswaroop.arrays;
+
+import me.ramswaroop.common.MaxHeap;
+
+import java.util.Arrays;
+
+/**
+ * Created by IntelliJ IDEA.
+ *
+ * @author: ramswaroop
+ * @date: 9/3/15
+ * @time: 9:21 PM
+ */
+public class MaxInAllSubArrays {
+
+    /**
+     * Finds the maximum element in each and every sub-array
+     * in {@param a} of size {@param k}.
+     * <p/>
+     * Time complexity: O(n^2)
+     *
+     * @param a
+     * @param k
+     */
+    public static int[] maxInAllSubArraysOfSizeKNaive(int[] a, int k) {
+        int[] maxElements = new int[a.length - k + 1];
+        int[] kElements;
+
+        for (int i = 0; i <= a.length - k; i++) {
+            kElements = Arrays.copyOfRange(a, i, i + k);
+            /**
+             * maxHeapify() can't be used because to call maxHeapify() on i, left(i) and right (i) should 
+             * already satisfy the max heap property which isn't true in this case.
+             */
+            MaxHeap.buildMaxHeap(kElements);
+            maxElements[i] = kElements[0];
+        }
+
+        return maxElements;
+    }
+
+    public static void main(String a[]) {
+        System.out.println(Arrays.toString(maxInAllSubArraysOfSizeKNaive(new int[]{1, 2, 3, 1, 4, 5, 2, 3, 6}, 3)));
+        System.out.println(Arrays.toString(maxInAllSubArraysOfSizeKNaive(new int[]{8, 5, 10, 7, 9, 4, 15, 12, 90, 13}, 4)));
+    }
+}