add 1394

Author: fishercoder1534

README.md

@@ -8,6 +8,7 @@ _If you like this project, please leave me a star._ ★
 
 |  #  |      Title     |   Solutions   | Video  | Difficulty  | Tag                   
 |-----|----------------|---------------|--------|-------------|-------------
+|1395|[Count Number of Teams](https://leetcode.com/problems/count-number-of-teams/)|[Solution](../master/src/main/java/com/fishercoder/solutions/_1395.java) | |Medium|Array|
 |1394|[Find Lucky Integer in an Array](https://leetcode.com/problems/find-lucky-integer-in-an-array/)|[Solution](../master/src/main/java/com/fishercoder/solutions/_1394.java) | |Easy|Array|
 |1392|[Longest Happy Prefix](https://leetcode.com/problems/longest-happy-prefix/)|[Solution](../master/src/main/java/com/fishercoder/solutions/_1392.java) | |Hard|String, Rolling Hash|
 |1390|[Four Divisors](https://leetcode.com/problems/four-divisors/)|[Solution](../master/src/main/java/com/fishercoder/solutions/_1390.java) | |Medium|Math|

src/main/java/com/fishercoder/solutions/_1395.java

@@ -0,0 +1,63 @@
+package com.fishercoder.solutions;
+
+/**
+ * 1395. Count Number of Teams
+ *
+ * There are n soldiers standing in a line. Each soldier is assigned a unique rating value.
+ * You have to form a team of 3 soldiers amongst them under the following rules:
+ * Choose 3 soldiers with index (i, j, k) with rating (rating[i], rating[j], rating[k]).
+ * A team is valid if:  (rating[i] < rating[j] < rating[k]) or (rating[i] > rating[j] > rating[k]) where (0 <= i < j < k < n).
+ * Return the number of teams you can form given the conditions. (soldiers can be part of multiple teams).
+ *
+ * Example 1:
+ * Input: rating = [2,5,3,4,1]
+ * Output: 3
+ * Explanation: We can form three teams given the conditions. (2,3,4), (5,4,1), (5,3,1).
+ *
+ * Example 2:
+ * Input: rating = [2,1,3]
+ * Output: 0
+ * Explanation: We can't form any team given the conditions.
+ *
+ * Example 3:
+ * Input: rating = [1,2,3,4]
+ * Output: 4
+ *
+ * Constraints:
+ * n == rating.length
+ * 1 <= n <= 200
+ * 1 <= rating[i] <= 10^5
+ * */
+public class _1395 {
+    public static class Solution1 {
+        public int numTeams(int[] rating) {
+            int count = 0;
+            //check increasing
+            for (int i = 0; i < rating.length - 2; i++) {
+                for (int j = i + 1; j < rating.length - 1; j++) {
+                    if (rating[j] > rating[i]) {
+                        for (int k = j + 1; k < rating.length; k++) {
+                            if (rating[k] > rating[j]) {
+                                count++;
+                            }
+                        }
+                    }
+                }
+            }
+
+            //check decreasing
+            for (int i = 0; i < rating.length - 2; i++) {
+                for (int j = i + 1; j < rating.length - 1; j++) {
+                    if (rating[j] < rating[i]) {
+                        for (int k = j + 1; k < rating.length; k++) {
+                            if (rating[k] < rating[j]) {
+                                count++;
+                            }
+                        }
+                    }
+                }
+            }
+            return count;
+        }
+    }
+}

src/test/java/com/fishercoder/_1395Test.java

@@ -0,0 +1,32 @@
+package com.fishercoder;
+
+import com.fishercoder.solutions._1395;
+import org.junit.BeforeClass;
+import org.junit.Test;
+
+import static org.junit.Assert.assertEquals;
+
+public class _1395Test {
+    private static _1395.Solution1 solution1;
+
+    @BeforeClass
+    public static void setup() {
+        solution1 = new _1395.Solution1();
+    }
+
+    @Test
+    public void test1() {
+        assertEquals(3, solution1.numTeams(new int[]{2, 5, 3, 4, 1}));
+    }
+
+    @Test
+    public void test2() {
+        assertEquals(0, solution1.numTeams(new int[]{2, 1, 3}));
+    }
+
+    @Test
+    public void test3() {
+        assertEquals(4, solution1.numTeams(new int[]{1, 2, 3, 4}));
+    }
+
+}