solve #3005: Count Elements With Maximum Frequency in java

Author: anishLearnsToCode

README.md

@@ -881,7 +881,7 @@
 | 2980 | [Check if Bitwise OR Has Trailing Zeros](https://leetcode.com/problems/check-if-bitwise-or-has-trailing-zeros)                                                         |                                                                              [![Java](assets/java.png)](src/CheckIfBitwiseORHasTrailingZeros.java)                                                                               |                                                                                                                                   |
 | 2996 | [Smallest Missing Integer Greater Than Sequential Prefix Sum](https://leetcode.com/problems/smallest-missing-integer-greater-than-sequential-prefix-sum)               |                                                                    [![Java](assets/java.png)](src/SmallestMissingIntegerGreaterThanSequentialPrefixSum.java)                                                                     |                                                                                                                                   |
 | 3000 | [Maximum Area of Longest Diagonal Rectangle](https://leetcode.com/problems/maximum-area-of-longest-diagonal-rectangle)                                                 |                                                                            [![Java](assets/java.png)](src/MaximumAreaOfLongestDiagonalRectangle.java)                                                                            |                                                                                                                                   |
-| 3005 | [Count Elements With Maximum Frequency](https://leetcode.com/problems/count-elements-with-maximum-frequency)                                                           |                                                                                                                                                                                                                                  |                                                                                                                                   |
+| 3005 | [Count Elements With Maximum Frequency](https://leetcode.com/problems/count-elements-with-maximum-frequency)                                                           |                                                                              [![Java](assets/java.png)](src/CountElementsWithMaximumFrequency.java)                                                                              |                                                                                                                                   |
 | 3010 | [Divide an Array Into Subarrays With Minimum Cost I](https://leetcode.com/problems/divide-an-array-into-subarrays-with-minimum-cost-i)                                 |                                                                                                                                                                                                                                  |                                                                                                                                   |
 | 3014 | [Minimum Number of Pushes to Type Word I](https://leetcode.com/problems/minimum-number-of-pushes-to-type-word-i)                                                       |                                                                                                                                                                                                                                  |                                                                                                                                   |
 | 3019 | [Number of Changing Keys](https://leetcode.com/problems/number-of-changing-keys)                                                                                       |                                                                                                                                                                                                                                  |                                                                                                                                   |

src/CountElementsWithMaximumFrequency.java

@@ -0,0 +1,36 @@
+// https://leetcode.com/problems/count-elements-with-maximum-frequency
+// T: O(N)
+// S: O(N)
+
+import java.util.HashMap;
+import java.util.Map;
+
+public class CountElementsWithMaximumFrequency {
+    public int maxFrequencyElements(int[] array) {
+        final Map<Integer, Integer> frequencies = computeFrequencies(array);
+        final int maxFrequency = getMaxFrequency(frequencies);
+        return numberOfElementsWithFrequency(frequencies, maxFrequency);
+    }
+
+    private static Map<Integer, Integer> computeFrequencies(int[] array) {
+        final Map<Integer, Integer> map = new HashMap<>();
+        for (int element : array) {
+            map.put(element, map.getOrDefault(element, 0) + 1);
+        }
+        return map;
+    }
+
+    private static int getMaxFrequency(final Map<Integer, Integer> frequencies) {
+        return frequencies.values().stream().max(Integer::compareTo).get();
+    }
+
+    private static int numberOfElementsWithFrequency(Map<Integer, Integer> frequencies, int frequency) {
+        int sum = 0;
+        for (Map.Entry<Integer,Integer> entry : frequencies.entrySet()) {
+            if (entry.getValue() == frequency) {
+                sum += frequency;
+            }
+        }
+        return sum;
+    }
+}