refactor 219

fishercoder1534 · fishercoder1534 · commit bb6bf1d6e21a · 2019-12-31T08:39:09.000-08:00
diff --git a/src/main/java/com/fishercoder/solutions/_219.java b/src/main/java/com/fishercoder/solutions/_219.java
@@ -1,13 +1,27 @@
 package com.fishercoder.solutions;
 
 import java.util.HashMap;
+import java.util.HashSet;
 import java.util.Map;
+import java.util.Set;
 
-/**219. Contains Duplicate II
-
+/**
+ * 219. Contains Duplicate II
  Given an array of integers and an integer k,
- find out whether there are two distinct indices i and j in
- the array such that nums[i] = nums[j] and the difference between i and j is at most k.
+ find out whether there are two distinct indices i and j in the array
+ such that nums[i] = nums[j] and the absolute difference between i and j is at most k.
+
+ Example 1:
+ Input: nums = [1,2,3,1], k = 3
+ Output: true
+
+ Example 2:
+ Input: nums = [1,0,1,1], k = 1
+ Output: true
+
+ Example 3:
+ Input: nums = [1,2,3,1,2,3], k = 2
+ Output: false
  */
 public class _219 {
 
@@ -28,4 +42,19 @@ public boolean containsNearbyDuplicate(int[] nums, int k) {
             return false;
         }
     }
+
+    public static class Solution2 {
+        public boolean containsNearbyDuplicate(int[] nums, int k) {
+            Set<Integer> set = new HashSet<>();
+            for (int i = 0; i < nums.length; i++) {
+                if (!set.add(nums[i])) {
+                    return true;
+                }
+                if (set.size() > k) {
+                    set.remove(nums[i - k]);
+                }
+            }
+            return false;
+        }
+    }
 }
diff --git a/src/test/java/com/fishercoder/_219Test.java b/src/test/java/com/fishercoder/_219Test.java
@@ -0,0 +1,32 @@
+package com.fishercoder;
+
+import com.fishercoder.solutions._219;
+import org.junit.BeforeClass;
+import org.junit.Test;
+
+import static junit.framework.Assert.assertEquals;
+
+public class _219Test {
+    private static _219.Solution1 solution1;
+    private static _219.Solution2 solution2;
+    private static int[] nums;
+
+    @BeforeClass
+    public static void setup() {
+        solution1 = new _219.Solution1();
+        solution2 = new _219.Solution2();
+    }
+
+    @Test
+    public void test1() {
+        nums = new int[]{1, 2, 3, 1};
+        assertEquals(true, solution1.containsNearbyDuplicate(nums, 3));
+    }
+
+    @Test
+    public void test2() {
+        nums = new int[]{1, 2, 3, 1};
+        assertEquals(true, solution2.containsNearbyDuplicate(nums, 3));
+    }
+
+}
