LeetCode-in-Java
1207. Unique Number of Occurrences
Easy
Given an array of integers arr, return true if the number of occurrences of each value in the array is unique, or false otherwise.
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
Solution
import java.util.HashMap;
import java.util.Map;
public class Solution {
public boolean uniqueOccurrences(int[] arr) {
Map<Integer, Integer> map = new HashMap<>();
for (int j : arr) {
if (map.containsKey(j)) {
map.put(j, map.get(j) + 1);
} else {
map.put(j, 1);
}
}
// map for check unique number of count
Map<Integer, Integer> uni = new HashMap<>();
for (Integer val : map.values()) {
if (uni.containsKey(val)) {
return false;
} else {
uni.put(val, 1);
}
}
return true;
}
}