add 1426

Author: fishercoder1534

README.md

@@ -11,6 +11,7 @@ _If you like this project, please leave me a star._ ★
 |1432|[Max Difference You Can Get From Changing an Integer](https://leetcode.com/problems/max-difference-you-can-get-from-changing-an-integer/)|[Solution](../master/src/main/java/com/fishercoder/solutions/_1432.java) | |Medium|String|
 |1431|[Kids With the Greatest Number of Candies](https://leetcode.com/problems/kids-with-the-greatest-number-of-candies/)|[Solution](../master/src/main/java/com/fishercoder/solutions/_1431.java) | |Easy|Array|
 |1423|[Maximum Points You Can Obtain from Cards](https://leetcode.com/problems/maximum-points-you-can-obtain-from-cards/)|[Solution](../master/src/main/java/com/fishercoder/solutions/_1423.java) | |Medium|Array, DP, Sliding Window|
+|1426|[Counting Elements](https://leetcode.com/problems/counting-elements/)|[Solution](../master/src/main/java/com/fishercoder/solutions/_1426.java) | |Easy|Array|
 |1422|[Maximum Score After Splitting a String](https://leetcode.com/problems/maximum-score-after-splitting-a-string/)|[Solution](../master/src/main/java/com/fishercoder/solutions/_1422.java) | |Easy|String|
 |1418|[Display Table of Food Orders in a Restaurant](https://leetcode.com/problems/display-table-of-food-orders-in-a-restaurant/)|[Solution](../master/src/main/java/com/fishercoder/solutions/_1418.java) | |Medium|HashTable|
 |1417|[Reformat The String](https://leetcode.com/problems/reformat-the-string/)|[Solution](../master/src/main/java/com/fishercoder/solutions/_1417.java) | |Easy|String|

src/main/java/com/fishercoder/solutions/_1426.java

@@ -0,0 +1,14 @@
+package com.fishercoder.solutions;
+
+import java.util.Arrays;
+import java.util.Set;
+import java.util.stream.Collectors;
+
+public class _1426 {
+    public static class Solution1 {
+        public int countElements(int[] arr) {
+            Set<Integer> set = Arrays.stream(arr).boxed().collect(Collectors.toSet());
+            return (int) Arrays.stream(arr).filter(n -> set.contains(n + 1)).count();
+        }
+    }
+}

src/test/java/com/fishercoder/_1426Test.java

@@ -0,0 +1,24 @@
+package com.fishercoder;
+
+import com.fishercoder.solutions._1426;
+import org.junit.BeforeClass;
+import org.junit.Test;
+
+import static junit.framework.TestCase.assertEquals;
+
+public class _1426Test {
+    private static _1426.Solution1 solution1;
+    private static int[] arr;
+
+    @BeforeClass
+    public static void setup() {
+        solution1 = new _1426.Solution1();
+    }
+
+    @Test
+    public void test1() {
+        arr = new int[]{1, 1, 3, 3, 5, 5, 7, 7};
+        assertEquals(0, solution1.countElements(arr));
+    }
+
+}