solves 2656: Maximum Sum With Exactly K Elements in java

Author: anishLearnsToCode

README.md

@@ -818,7 +818,7 @@
 | 2644 | [Find the Maximum Divisibility Score](https://leetcode.com/problems/find-the-maximum-divisibility-score)                                                               |                                                                               [![Java](assets/java.png)](src/FindTheMaximumDivisibilityScore.java)                                                                               |                                                                                                                                   |
 | 2651 | [Calculate Delayed Arrival Time](https://leetcode.com/problems/calculate-delayed-arrival-time)                                                                         |                                                                                 [![Java](assets/java.png)](src/CalculateDelayedArrivalTime.java)                                                                                 |                                                                                                                                   |
 | 2652 | [Sum Multiples](https://leetcode.com/problems/sum-multiples)                                                                                                           |                                                                                        [![Java](assets/java.png)](src/SumMultiples.java)                                                                                         |                                                                                                                                   |
-| 2656 | [Maximum Sum With Exactly K Elements](https://leetcode.com/problems/maximum-sum-with-exactly-k-elements)                                                               |                                                                                                                                                                                                                                  |                                                                                                                                   |
+| 2656 | [Maximum Sum With Exactly K Elements](https://leetcode.com/problems/maximum-sum-with-exactly-k-elements)                                                               |                                                                               [![Java](assets/java.png)](src/MaximumSumWithExactlyKElements.java)                                                                                |                                                                                                                                   |
 | 2660 | [Determine the Winner of a Bowling Game](https://leetcode.com/problems/determine-the-winner-of-a-bowling-game)                                                         |                                                                                                                                                                                                                                  |                                                                                                                                   |
 | 2670 | [Find the Distinct Difference Array](https://leetcode.com/problems/find-the-distinct-difference-array)                                                                 |                                                                                                                                                                                                                                  |                                                                                                                                   |
 | 2678 | [Number of Senior Citizens](https://leetcode.com/problems/number-of-senior-citizens)                                                                                   |                                                                                                                                                                                                                                  |                                                                                                                                   |

src/MaximumSumWithExactlyKElements.java

@@ -0,0 +1,16 @@
+// https://leetcode.com/problems/maximum-sum-with-exactly-k-elements
+// T: O(n)
+// S: O(1)
+
+import java.util.Arrays;
+
+public class MaximumSumWithExactlyKElements {
+    public int maximizeSum(int[] nums, int k) {
+        final int maxElement = Arrays.stream(nums).max().getAsInt();
+        return maxElement * k + summation(k - 1);
+    }
+
+    private int summation(int x) {
+        return (x * (x + 1)) / 2;
+    }
+}