add 1583

Author: fishercoder1534

README.md

@@ -8,6 +8,7 @@ _If you like this project, please leave me a star._ ★
 
 |  #  |      Title     |   Solutions   | Video  | Difficulty  | Tag                   
 |-----|----------------|---------------|--------|-------------|-------------
+|1583|[Count Unhappy Friends](https://leetcode.com/problems/count-unhappy-friends/)|[Solution](../master/src/main/java/com/fishercoder/solutions/_1583.java) ||Array|Medium|
 |1582|[Special Positions in a Binary Matrix](https://leetcode.com/problems/special-positions-in-a-binary-matrix/)|[Solution](../master/src/main/java/com/fishercoder/solutions/_1582.java) ||Array|Easy|
 |1576|[Replace All ?'s to Avoid Consecutive Repeating Characters](https://leetcode.com/problems/replace-all-s-to-avoid-consecutive-repeating-characters/)|[Solution](../master/src/main/java/com/fishercoder/solutions/_1576.java) |[:tv:](https://youtu.be/SJBDLYqrIsM)|String|Easy|
 |1574|[Shortest Subarray to be Removed to Make Array Sorted](https://leetcode.com/problems/shortest-subarray-to-be-removed-to-make-array-sorted/)|[Solution](../master/src/main/java/com/fishercoder/solutions/_1574.java) ||Array, Binary Search|Medium|

src/main/java/com/fishercoder/solutions/_1583.java

@@ -0,0 +1,61 @@
+package com.fishercoder.solutions;
+
+import java.util.HashMap;
+import java.util.Map;
+
+public class _1583 {
+    public static class Solution1 {
+        public int unhappyFriends(int n, int[][] preferences, int[][] pairs) {
+            int unhappyFriends = 0;
+            Map<Integer, Integer> assignedPair = new HashMap<>();
+            for (int[] pair : pairs) {
+                assignedPair.put(pair[0], pair[1]);
+                assignedPair.put(pair[1], pair[0]);
+            }
+            for (int[] pair : pairs) {
+                if (isUnHappy(pair[1], pair[0], preferences, assignedPair)) {
+                    unhappyFriends++;
+                }
+                if (isUnHappy(pair[0], pair[1], preferences, assignedPair)) {
+                    unhappyFriends++;
+                }
+            }
+            return unhappyFriends;
+        }
+
+        private boolean isUnHappy(int self, int assignedFriend, int[][] preferences, Map<Integer, Integer> assignedPairs) {
+            int[] preference = preferences[self];
+            int assignedFriendPreferenceIndex = findIndex(preference, assignedFriend);
+            for (int i = 0; i <= assignedFriendPreferenceIndex; i++) {
+                int preferredFriend = preference[i];
+                int preferredFriendAssignedFriend = assignedPairs.get(preferredFriend);
+                if (preferredFriendAssignedFriend == self) {
+                    return false;
+                }
+                int candidateAssignedFriendIndex = findIndex(preferences[preferredFriend], preferredFriendAssignedFriend);
+                if (isPreferred(self, preferences[preferredFriend], candidateAssignedFriendIndex)) {
+                    return true;
+                }
+            }
+            return false;
+        }
+
+        private boolean isPreferred(int self, int[] preference, int boundary) {
+            for (int i = 0; i <= boundary; i++) {
+                if (self == preference[i]) {
+                    return true;
+                }
+            }
+            return false;
+        }
+
+        private int findIndex(int[] preference, int assignedFriend) {
+            for (int i = 0; i < preference.length; i++) {
+                if (preference[i] == assignedFriend) {
+                    return i;
+                }
+            }
+            return 0;
+        }
+    }
+}

src/test/java/com/fishercoder/_1583Test.java

@@ -0,0 +1,31 @@
+package com.fishercoder;
+
+import com.fishercoder.solutions._1583;
+import org.junit.BeforeClass;
+import org.junit.Test;
+
+import static junit.framework.TestCase.assertEquals;
+
+public class _1583Test {
+    private static _1583.Solution1 solution1;
+
+    @BeforeClass
+    public static void setup() {
+        solution1 = new _1583.Solution1();
+    }
+
+    @Test
+    public void test1() {
+        assertEquals(2, solution1.unhappyFriends(4, new int[][]{
+                        {1, 2, 3},
+                        {3, 2, 0},
+                        {3, 1, 0},
+                        {1, 2, 0}
+                },
+                new int[][]{
+                        {0, 1},
+                        {2, 3}
+                }));
+    }
+
+}