| # | 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||

packagecom.fishercoder.solutions;

importjava.util.Arrays;

importjava.util.HashMap;

importjava.util.HashSet;

importjava.util.Map;

importjava.util.Set;

publicclass_1207 {

publicstaticclassSolution1 {

publicbooleanuniqueOccurrences(int[]arr) {

Map<Integer,Integer>map =newHashMap<>();

Arrays.stream(arr).forEach(num -> {

map.put(num,map.containsKey(num) ?map.get(num) +1 :1);

});

Set<Integer>set =newHashSet<>();

returnmap.keySet().stream().mapToInt(key ->key).allMatch(key ->set.add(map.get(key)));

}

}

}

packagecom.fishercoder;

importcom.fishercoder.solutions._1207;

importorg.junit.BeforeClass;

importorg.junit.Test;

importstaticorg.junit.Assert.assertEquals;

publicclass_1207Test {

privatestatic_1207.Solution1solution1;

privatestaticint[]arr;

publicstaticvoidsetup() {

solution1 =new_1207.Solution1();

}

publicvoidtest1() {

arr =newint[]{1,2,2,1,1,3};

assertEquals(true,solution1.uniqueOccurrences(arr));

}

publicvoidtest2() {

arr =newint[]{1,2};

assertEquals(false,solution1.uniqueOccurrences(arr));

}

publicvoidtest3() {

arr =newint[]{-3,0,1, -3,1,1,1, -3,10,0};

assertEquals(true,solution1.uniqueOccurrences(arr));

}

}