solves find the luckt number ina n array

Author: anishLearnsToCode

README.md

@@ -354,7 +354,7 @@
 | 1380 | [Lucky Numbers In A Matrix](https://leetcode.com/problems/lucky-numbers-in-a-matrix)                                                                 |                                                              [![Java](assets/java.png)](src/LuckyNumbersInAMatrix.java)                                                              |                                                                                                                                   |
 | 1385 | [Find The Distance Value Between 2 Arrays](https://leetcode.com/problems/find-the-distance-value-between-two-arrays)                                 |                                                      [![Java](assets/java.png)](src/FindTheDistanceValuesBetweenTwoArrays.java)                                                      |                                                                                                                                   |
 | 1389 | [Create Target Array in Given Order](https://leetcode.com/problems/create-target-array-in-the-given-order)                                           |                                                          [![Java](assets/java.png)](src/CreateTargetArrayInGivenOrder.java)                                                          |                                                                                                                                   |
-| 1394 | [Find Lucky Integer In An Array](https://leetcode.com/problems/find-lucky-integer-in-an-array)                                                       |                                                                                                                                                                                      |                                                                                                                                   |
+| 1394 | [Find Lucky Integer In An Array](https://leetcode.com/problems/find-lucky-integer-in-an-array)                                                       |                                                          [![Java](assets/java.png)](src/FindTheLuckyIntegerInAnArray.java)                                                           |                                                                                                                                   |
 | 1399 | [Count Largest Group](https://leetcode.com/problems/count-largest-group)                                                                             |                                                                                                                                                                                      |                                                                                                                                   |
 | 1403 | [Minimum Subsequence in Non-Increasing Order](https://leetcode.com/problems/minimum-subsequence-in-non-increasing-order)                             |                                                                                                                                                                                      |                                                                                                                                   |
 | 1408 | [String Matching In An Array](https://leetcode.com/problems/string-matching-in-an-array)                                                             |                                                                                                                                                                                      |                                                                                                                                   |

src/FindTheLuckyIntegerInAnArray.java

@@ -0,0 +1,32 @@
+import java.util.Comparator;
+import java.util.HashMap;
+import java.util.Map;
+import java.util.PriorityQueue;
+import java.util.Queue;
+
+public class FindTheLuckyIntegerInAnArray {
+    public int findLucky(int[] array) {
+        Map<Integer, Integer> frequencies = getFrequencies(array);
+        Queue<Integer> luckyIntegers = getLuckyIntegers(frequencies);
+        if (luckyIntegers.isEmpty()) return -1;
+        return luckyIntegers.poll();
+    }
+
+    private Map<Integer, Integer> getFrequencies(int[] array) {
+        Map<Integer, Integer> frequencies = new HashMap<>();
+        for (int element : array) {
+            frequencies.put(element, frequencies.getOrDefault(element, 0) + 1);
+        }
+        return frequencies;
+    }
+
+    private Queue<Integer> getLuckyIntegers(Map<Integer, Integer> frequencies){
+        Queue<Integer> luckyNumbers = new PriorityQueue<>(Comparator.reverseOrder());
+        for (Map.Entry<Integer, Integer> entry : frequencies.entrySet()) {
+            if (entry.getKey() == entry.getValue()) {
+                luckyNumbers.add(entry.getValue());
+            }
+        }
+        return luckyNumbers;
+    }
+}