[LeetCode] 1207. Unique Number of Occurrences()-其他

[LeetCode] 1207. Unique Number of Occurrences()

Given an array of integers , return  if the number of occurrences of each value in the array is unique, or  otherwise.

``arr``
``true``
``false``

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

Java实现

`````` 1 class Solution {
2     public boolean uniqueOccurrences(int[] arr) {
3         HashMap<Integer, Integer> map = new HashMap<>();
4         for (int num : arr) {
5             map.put(num, map.getOrDefault(num, 0) + 1);
6         }
7
8         HashSet<Integer> set = new HashSet<>();
9         for (int val : map.values()) {
11                 return false;
12             }
13         }
14         return true;
15     }
16 }``````

LeetCode 题目总结

————————

Given an array of integers , return  if the number of occurrences of each value in the array is unique, or  otherwise.

``arr``
``true``
``false``

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

Java实现

`````` 1 class Solution {
2     public boolean uniqueOccurrences(int[] arr) {
3         HashMap<Integer, Integer> map = new HashMap<>();
4         for (int num : arr) {
5             map.put(num, map.getOrDefault(num, 0) + 1);
6         }
7
8         HashSet<Integer> set = new HashSet<>();
9         for (int val : map.values()) {