solves x of a kind in a deck of cards

Author: anishLearnsToCode

README.md

@@ -246,7 +246,7 @@
 | 897 | [Increasing Order Search Tree](https://leetcode.com/problems/increasing-order-search-tree) | [![Java](assets/java.png)](src/IncreasingOrderSearchTree.java) |
 | 905 | [Sort Array by Parity](https://leetcode.com/problems/sort-array-by-parity) | |
 | 908 | [Smallest Range I](https://leetcode.com/problems/smallest-range-i) | [![Java](assets/java.png)](src/SmallestRangeI.java) |
-| 914 | [X of a kind in a Deck of Cards](https://leetcode.com/problems/x-of-a-kind-in-a-deck-of-cards) | |
+| 914 | [X of a kind in a Deck of Cards](https://leetcode.com/problems/x-of-a-kind-in-a-deck-of-cards) | [![Java](assets/java.png)](src/XOfAKindInADeckOfCards.java) |
 | 917 | [Reverse Only Letters](https://leetcode.com/problems/reverse-only-letters) | |
 | 922 | [Sort Array by Parity II](https://leetcode.com/problems/sort-array-by-parity-ii) | |
 | 925 | [Long Pressed Name](https://leetcode.com/problems/long-pressed-name) | |

src/XOfAKindInADeckOfCards.java

@@ -0,0 +1,37 @@
+import java.util.Collection;
+import java.util.HashMap;
+import java.util.HashSet;
+import java.util.Map;
+import java.util.Set;
+
+public class XOfAKindInADeckOfCards {
+    public boolean hasGroupsSizeX(int[] deck) {
+        if (deck.length == 1) return false;
+        Map<Integer, Integer> cards = getFrequencies(deck);
+        Set<Integer> frequencies = new HashSet<>(cards.values());
+        if (frequencies.size() == 1 && cards.get(deck[0]) >= 2) return true;
+        return gcd(frequencies) > 1;
+    }
+
+    private int gcd(Collection<Integer> collection) {
+        int gcd = 0;
+        boolean firstTime = true;
+        for (int value : collection) {
+            gcd = firstTime ? value : gcd(gcd, value);
+            firstTime = false;
+        }
+        return gcd;
+    }
+
+    private int gcd(int a, int b) {
+        return b == 0 ? a : gcd(b, a % b);
+    }
+
+    private Map<Integer, Integer> getFrequencies(int[] array) {
+        Map<Integer, Integer> result = new HashMap<>();
+        for (int val : array) {
+            result.put(val, result.getOrDefault(val, 0) + 1);
+        }
+        return result;
+    }
+}