add 950

fishercoder1534 · fishercoder1534 · commit 8d5a662272ce · 2019-02-24T18:25:01.000-08:00
diff --git a/README.md b/README.md
@@ -42,6 +42,7 @@ Your ideas/fixes/algorithms are more than welcome!
 |965|[Univalued Binary Tree](https://leetcode.com/problems/univalued-binary-tree/)|[Solution](../master/src/main/java/com/fishercoder/solutions/_965.java) | O(n) | O(h) | |Easy| DFS, recursion|
 |961|[N-Repeated Element in Size 2N Array](https://leetcode.com/problems/n-repeated-element-in-size-2n-array/)|[Solution](../master/src/main/java/com/fishercoder/solutions/_961.java) | O(n) | O(1) | |Easy|
 |953|[Verifying an Alien Dictionary](https://leetcode.com/problems/verifying-an-alien-dictionary/)|[Solution](../master/src/main/java/com/fishercoder/solutions/_953.java) | O(1) | O(1) | |Easy|
+|950|[Reveal Cards In Increasing Order](https://leetcode.com/problems/reveal-cards-in-increasing-order/)|[Solution](../master/src/main/java/com/fishercoder/solutions/_950.java) | O(nlogn) | O(n) | |Medium|
 |944|[Delete Columns to Make Sorted](https://leetcode.com/problems/delete-columns-to-make-sorted/)|[Solution](../master/src/main/java/com/fishercoder/solutions/_944.java) | O(n) | O(1) | |Easy|
 |942|[DI String Match](https://leetcode.com/problems/di-string-match/)|[Solution](../master/src/main/java/com/fishercoder/solutions/_942.java) | O(n) | O(n) | |Easy|
 |941|[Valid Mountain Array](https://leetcode.com/problems/valid-mountain-array/)|[Solution](../master/src/main/java/com/fishercoder/solutions/_941.java) | O(n) | O(1) | |Easy|
diff --git a/src/main/java/com/fishercoder/solutions/_950.java b/src/main/java/com/fishercoder/solutions/_950.java
@@ -0,0 +1,60 @@
+package com.fishercoder.solutions;
+
+import java.util.ArrayDeque;
+import java.util.Arrays;
+import java.util.Deque;
+
+/**
+ * 950. Reveal Cards In Increasing Order
+ *
+ * In a deck of cards, every card has a unique integer.  You can order the deck in any order you want.
+ * Initially, all the cards start face down (unrevealed) in one deck.
+ * Now, you do the following steps repeatedly, until all cards are revealed:
+ * Take the top card of the deck, reveal it, and take it out of the deck.
+ * If there are still cards in the deck, put the next top card of the deck at the bottom of the deck.
+ * If there are still unrevealed cards, go back to step 1.  Otherwise, stop.
+ * Return an ordering of the deck that would reveal the cards in increasing order.
+ *
+ * The first entry in the answer is considered to be the top of the deck.
+ *
+ * Example 1:
+ * Input: [17,13,11,2,3,5,7]
+ * Output: [2,13,3,11,5,17,7]
+ *
+ * Explanation:
+ * We get the deck in the order [17,13,11,2,3,5,7] (this order doesn't matter), and reorder it.
+ * After reordering, the deck starts as [2,13,3,11,5,17,7], where 2 is the top of the deck.
+ * We reveal 2, and move 13 to the bottom.  The deck is now [3,11,5,17,7,13].
+ * We reveal 3, and move 11 to the bottom.  The deck is now [5,17,7,13,11].
+ * We reveal 5, and move 17 to the bottom.  The deck is now [7,13,11,17].
+ * We reveal 7, and move 13 to the bottom.  The deck is now [11,17,13].
+ * We reveal 11, and move 17 to the bottom.  The deck is now [13,17].
+ * We reveal 13, and move 17 to the bottom.  The deck is now [17].
+ * We reveal 17.
+ * Since all the cards revealed are in increasing order, the answer is correct.
+ *
+ * Note:
+ * 1 <= A.length <= 1000
+ * 1 <= A[i] <= 10^6
+ * A[i] != A[j] for all i != j
+ */
+public class _950 {
+  public static class Solution1 {
+    public int[] deckRevealedIncreasing(int[] deck) {
+      Arrays.sort(deck);
+      Deque<Integer> deque = new ArrayDeque<>();
+      for (int i = deck.length - 1; i >= 0; i--) {
+        if (i != deck.length - 1) {
+          deque.addFirst(deque.pollLast());
+        }
+        deque.addFirst(deck[i]);
+      }
+      int[] result = new int[deck.length];
+      int i = 0;
+      while (!deque.isEmpty()) {
+        result[i++] = deque.pollFirst();
+      }
+      return result;
+    }
+  }
+}
diff --git a/src/test/java/com/fishercoder/_950Test.java b/src/test/java/com/fishercoder/_950Test.java
@@ -0,0 +1,22 @@
+package com.fishercoder;
+
+import com.fishercoder.solutions._950;
+import org.junit.BeforeClass;
+import org.junit.Test;
+
+import static org.junit.Assert.assertArrayEquals;
+
+public class _950Test {
+  private static _950.Solution1 solution1;
+
+  @BeforeClass
+  public static void setup() {
+    solution1 = new _950.Solution1();
+  }
+
+  @Test
+  public void test1() {
+    assertArrayEquals(new int[] {2, 13, 3, 11, 5, 17, 7},
+        solution1.deckRevealedIncreasing(new int[] {17, 13, 11, 2, 3, 5, 7}));
+  }
+}
