add 1207

fishercoder1534 · zhahui · commit a7aaf4754643 · 2019-10-26T14:34:43.000-04:00
diff --git a/README.md b/README.md
@@ -27,6 +27,7 @@ Your ideas/fixes/algorithms are more than welcome!
 
 |  #  |      Title     |   Solutions   | Time          | Space         | Video  | Difficulty  | Tag                   
 |-----|----------------|---------------|---------------|---------------|--------|-------------|-------------
+|1207|[Unique Number of Occurrences](https://leetcode.com/problems/unique-number-of-occurrences/)|[Solution](../master/src/main/java/com/fishercoder/solutions/_1207.java) | O(n) | O(1) | |Easy||
 |1160|[Find Words That Can Be Formed by Characters](https://leetcode.com/problems/find-words-that-can-be-formed-by-characters/)|[Solution](../master/src/main/java/com/fishercoder/solutions/_1160.java) | O(n) | O(m) | |Easy||
 |1154|[Day of the Year](https://leetcode.com/problems/day-of-the-year/)|[Solution](../master/src/main/java/com/fishercoder/solutions/_1154.java) | O(1) | O(1) | |Easy||
 |1137|[N-th Tribonacci Number](https://leetcode.com/problems/n-th-tribonacci-number/)|[Solution](../master/src/main/java/com/fishercoder/solutions/_1137.java) | O(n) | O(n) | |Easy||
diff --git a/src/main/java/com/fishercoder/solutions/_1207.java b/src/main/java/com/fishercoder/solutions/_1207.java
@@ -0,0 +1,43 @@
+package com.fishercoder.solutions;
+
+import java.util.Arrays;
+import java.util.HashMap;
+import java.util.HashSet;
+import java.util.Map;
+import java.util.Set;
+
+/**
+ * 1207. Unique Number of Occurrences
+ *
+ * Given an array of integers arr,
+ * write a function that returns true if and only if the number of occurrences of each value in the array is unique.
+ *
+ * Example 1:
+ * Input: arr = [1,2,2,1,1,3]
+ * Output: true
+ * Explanation: The value 1 has 3 occurrences, 2 has 2 and 3 has 1. No two values have the same number of occurrences.
+ *
+ * Example 2:
+ * Input: arr = [1,2]
+ * Output: false
+ *
+ * Example 3:
+ * Input: arr = [-3,0,1,-3,1,1,1,-3,10,0]
+ * Output: true
+ *
+ * Constraints:
+ * 1 <= arr.length <= 1000
+ * -1000 <= arr[i] <= 1000
+ * */
+public class _1207 {
+    public static class Solution1 {
+        public boolean uniqueOccurrences(int[] arr) {
+            Map<Integer, Integer> map = new HashMap<>();
+            Arrays.stream(arr).forEach(num -> {
+                map.put(num, map.containsKey(num) ? map.get(num) + 1 : 1);
+            });
+            Set<Integer> set = new HashSet<>();
+            return map.keySet().stream().mapToInt(key -> key).allMatch(key -> set.add(map.get(key)));
+        }
+    }
+}
diff --git a/src/test/java/com/fishercoder/_1207Test.java b/src/test/java/com/fishercoder/_1207Test.java
@@ -0,0 +1,35 @@
+package com.fishercoder;
+
+import com.fishercoder.solutions._1207;
+import org.junit.BeforeClass;
+import org.junit.Test;
+
+import static org.junit.Assert.assertEquals;
+
+public class _1207Test {
+    private static _1207.Solution1 solution1;
+    private static int[] arr;
+
+    @BeforeClass
+    public static void setup() {
+        solution1 = new _1207.Solution1();
+    }
+
+    @Test
+    public void test1() {
+        arr = new int[]{1, 2, 2, 1, 1, 3};
+        assertEquals(true, solution1.uniqueOccurrences(arr));
+    }
+
+    @Test
+    public void test2() {
+        arr = new int[]{1, 2};
+        assertEquals(false, solution1.uniqueOccurrences(arr));
+    }
+
+    @Test
+    public void test3() {
+        arr = new int[]{-3, 0, 1, -3, 1, 1, 1, -3, 10, 0};
+        assertEquals(true, solution1.uniqueOccurrences(arr));
+    }
+}
