refactor 941

fishercoder1534 · fishercoder1534 · commit 73b7281dd714 · 2018-11-18T15:00:02.000-08:00
diff --git a/README.md b/README.md
@@ -29,6 +29,7 @@ Your ideas/fixes/algorithms are more than welcome!
 
 |  #  |      Title     |   Solutions   | Time          | Space         | Video  | Difficulty  | Tag                   
 |-----|----------------|---------------|---------------|---------------|--------|-------------|-------------
+|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|
 |933|[Number of Recent Calls](https://leetcode.com/problems/number-of-recent-calls/)|[Solution](../master/src/main/java/com/fishercoder/solutions/_933.java) | O(n) | O(n) | |Easy|
 |929|[Unique Email Addresses](https://leetcode.com/problems/unique-email-addresses/)|[Solution](../master/src/main/java/com/fishercoder/solutions/_929.java) | O(n) | O(n) | |Easy|
 |922|[Sort Array By Parity II](https://leetcode.com/problems/sort-array-by-parity-ii/)|[Solution](../master/src/main/java/com/fishercoder/solutions/_922.java) | O(n) | O(1) | |Easy|
diff --git a/src/main/java/com/fishercoder/solutions/_941.java b/src/main/java/com/fishercoder/solutions/_941.java
@@ -0,0 +1,61 @@
+package com.fishercoder.solutions;
+
+/**
+ * 941. Valid Mountain Array
+ *
+ * Given an array A of integers, return true if and only if it is a valid mountain array.
+ *
+ * Recall that A is a mountain array if and only if:
+ *
+ * A.length >= 3
+ * There exists some i with 0 < i < A.length - 1 such that:
+ * A[0] < A[1] < ... A[i-1] < A[i]
+ * A[i] > A[i+1] > ... > A[B.length - 1]
+ *
+ *
+ * Example 1:
+ *
+ * Input: [2,1]
+ * Output: false
+ * Example 2:
+ *
+ * Input: [3,5,5]
+ * Output: false
+ * Example 3:
+ *
+ * Input: [0,3,2,1]
+ * Output: true
+ *
+ *
+ * Note:
+ *
+ * 0 <= A.length <= 10000
+ * 0 <= A[i] <= 10000
+ * */
+public class _941 {
+    public static class Solution1 {
+        public boolean validMountainArray(int[] A) {
+            int i = 0;
+            for (; i < A.length - 1; i++) {
+                if (A[i] < A[i+1]) {
+                    continue;
+                } else if (A[i] == A[i+1]) {
+                    return false;
+                } else {
+                    break;
+                }
+            }
+            if (i == 0 || i >= A.length - 1) {
+                return false;
+            }
+            for (; i < A.length-1; i++) {
+                if (A[i] > A[i+1]) {
+                    continue;
+                } else {
+                    return false;
+                }
+            }
+            return i == A.length - 1;
+        }
+    }
+}
diff --git a/src/test/java/com/fishercoder/_941Test.java b/src/test/java/com/fishercoder/_941Test.java
@@ -0,0 +1,42 @@
+package com.fishercoder;
+
+import com.fishercoder.solutions._941;
+import org.junit.BeforeClass;
+import org.junit.Test;
+
+import static org.junit.Assert.assertEquals;
+
+public class _941Test {
+    private static _941.Solution1 solution1;
+    private static int[] A;
+
+    @BeforeClass
+    public static void setup() {
+        solution1 = new _941.Solution1();
+    }
+
+    @Test
+    public void test1() {
+        A = new int[]{0, 3, 2, 1};
+        assertEquals(true, solution1.validMountainArray(A));
+    }
+
+    @Test
+    public void test2() {
+        A = new int[]{2, 1};
+        assertEquals(false, solution1.validMountainArray(A));
+    }
+
+    @Test
+    public void test3() {
+        A = new int[]{3, 5, 5};
+        assertEquals(false, solution1.validMountainArray(A));
+    }
+
+    @Test
+    public void test4() {
+        A = new int[]{0, 1, 2, 3, 4, 5, 6, 7, 8, 9};
+        assertEquals(false, solution1.validMountainArray(A));
+    }
+
+}
