solves #2526: Find the Array Concatenation Value in java

Author: anishLearnsToCode

README.md

@@ -799,8 +799,8 @@
 | 2544 | [Alternating Digit Sum](https://leetcode.com/problems/alternating-digit-sum)                                                                                           |                                                                                     [![Java](assets/java.png)](src/AlternatingDigitSum.java)                                                                                     |                                                                                                                                   |
 | 2549 | [Count Distinct Numbers on Board](https://leetcode.com/problems/count-distinct-numbers-on-board)                                                                       |                                                                                 [![Java](assets/java.png)](src/CountDistinctNumbersOnBoard.java)                                                                                 |                                                                                                                                   |
 | 2553 | [Separate the Digits in an Array](https://leetcode.com/problems/separate-the-digits-in-an-array)                                                                       |                                                                                 [![Java](assets/java.png)](src/SeparateTheDigitsInAnArray.java)                                                                                  |                                                                                                                                   |
-| 2558 | [Take Gifts From the Richest Pile](https://leetcode.com/problems/take-gifts-from-the-richest-pile)                                                                     |                                                                                                                                                                                                                                  |                                                                                                                                   |
-| 2562 | [Find the Array Concatenation Value](https://leetcode.com/problems/find-the-array-concatenation-value)                                                                 |                                                                                                                                                                                                                                  |                                                                                                                                   |
+| 2558 | [Take Gifts From the Richest Pile](https://leetcode.com/problems/take-gifts-from-the-richest-pile)                                                                     |                                                                                 [![Java](assets/java.png)](src/TakeGiftsFromTheRichestPile.java)                                                                                 |                                                                                                                                   |
+| 2562 | [Find the Array Concatenation Value](https://leetcode.com/problems/find-the-array-concatenation-value)                                                                 |                                                                               [![Java](assets/java.png)](src/FindTheArrayConcatenationValue.java)                                                                                |                                                                                                                                   |
 | 2566 | [Maximum Difference by Remapping a Digit](https://leetcode.com/problems/maximum-difference-by-remapping-a-digit)                                                       |                                                                                                                                                                                                                                  |                                                                                                                                   |
 | 2570 | [Merge Two 2D Arrays by Summing Values](https://leetcode.com/problems/merge-two-2d-arrays-by-summing-values)                                                           |                                                                                                                                                                                                                                  |                                                                                                                                   |
 | 2574 | [Left and Right Sum Differences](https://leetcode.com/problems/left-and-right-sum-differences)                                                                         |                                                                                                                                                                                                                                  |                                                                                                                                   |

src/FindTheArrayConcatenationValue.java

@@ -0,0 +1,19 @@
+// https://leetcode.com/problems/find-the-array-concatenation-value
+// T: O(N)
+// S: O(1)
+
+public class FindTheArrayConcatenationValue {
+    public long findTheArrayConcVal(int[] nums) {
+        long result = 0;
+
+        for (int i = 0 ; i < nums.length / 2 ; i++) {
+            result += Integer.parseInt(nums[i] + "" + nums[nums.length - 1 - i]);
+        }
+
+        if (nums.length % 2 == 1) {
+            result += nums[nums.length / 2];
+        }
+
+        return result;
+    }
+}

src/TakeGiftsFromTheRichestPile.java

@@ -0,0 +1,37 @@
+// https://leetcode.com/problems/take-gifts-from-the-richest-pile
+// T: O(k * log(N))
+// S: O(N)
+
+import java.util.Comparator;
+import java.util.PriorityQueue;
+import java.util.Queue;
+
+public class TakeGiftsFromTheRichestPile {
+    public long pickGifts(int[] gifts, int k) {
+        final Queue<Integer> maxHeap = maHeapFrom(gifts);
+
+        for (int i = 0 ; i < k ; i++) {
+            final int maxPile = maxHeap.poll();
+            final int giftsToLeaveBehind = (int) Math.max(Math.sqrt(maxPile), 0);
+            maxHeap.add(giftsToLeaveBehind);
+        }
+
+        return sum(maxHeap);
+    }
+
+    private long sum(Queue<Integer> heap) {
+        long sum = 0;
+        while (!heap.isEmpty()) {
+            sum += heap.poll();
+        }
+        return sum;
+    }
+
+    private Queue<Integer> maHeapFrom(int[] array) {
+        final Queue<Integer> maxHeap = new PriorityQueue<>(Comparator.reverseOrder());
+        for (int element : array) {
+            maxHeap.add(element);
+        }
+        return maxHeap;
+    }
+}