From 5c968ef14904afda02439a11bec63a0153372cf6 Mon Sep 17 00:00:00 2001
From: Matej Focko <me@mfocko.xyz>
Date: Thu, 6 Jun 2024 11:38:33 +0200
Subject: [PATCH] =?UTF-8?q?java:=20add=20=C2=AB846.=20Hand=20of=20Straight?=
 =?UTF-8?q?s=C2=BB?=
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Signed-off-by: Matej Focko <me@mfocko.xyz>
---
 java/hand-of-straights.java | 34 ++++++++++++++++++++++++++++++++++
 1 file changed, 34 insertions(+)
 create mode 100644 java/hand-of-straights.java

diff --git a/java/hand-of-straights.java b/java/hand-of-straights.java
new file mode 100644
index 0000000..e21f0ac
--- /dev/null
+++ b/java/hand-of-straights.java
@@ -0,0 +1,34 @@
+import java.util.TreeMap;
+
+class Solution {
+  public boolean isNStraightHand(int[] hand, int groupSize) {
+    if (hand.length % groupSize != 0) {
+      return false;
+    }
+
+    TreeMap<Integer, Integer> cards = new TreeMap<>();
+    for (int card : hand) {
+      cards.compute(card, (c, present) -> 1 + ((present == null) ? 0 : present));
+    }
+
+    while (!cards.isEmpty()) {
+      int card = cards.entrySet().iterator().next().getKey();
+
+      for (int i = 0; i < groupSize; ++i) {
+        // card doesn't exist
+        if (!cards.containsKey(card + i)) {
+          return false;
+        }
+
+        cards.put(card + i, cards.get(card + i) - 1);
+
+        // remove entry of used cards
+        if (cards.get(card + i) == 0) {
+          cards.remove(card + i);
+        }
+      }
+    }
+
+    return true;
+  }
+}