1207 Unique Number of Occurrences 1

Joel Castillo Espinosa 2

DESCRIPTION

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

Examples

  • 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 3

unique_occ <- function(arr){
  # find the unique values in arr
  unique_val <- unique(arr)
  
  # in each iteration, save the occurrences of i-element in arr
  vec_occ <- c() # vector of occurrences 
  for (i in unique_val) {
    vec_occ <- c(vec_occ, sum(arr == i))
  }
  
  # if each value has a different occurrence, the total number of 
    # unique values is equal to the number of unique occurrences 
    # in the vector vec_occ
  result <- length(unique_val) == length(unique(vec_occ))
  
  print(result)
}

Examples using the function

We can use the examples presented before.

unique_occ(c(1,2,2,1,1,3))

## [1] TRUE

unique_occ(c(1,2))

## [1] FALSE

unique_occ(c(-3,0,1,-3,1,1,1,-3,10,0))

## [1] TRUE

  1. This problem is originally from LeetCode, you can find it in Leetcode. ↩

  2. Email: jocastillo@colmex.mx. For more content visit my website: https://joelcastillo.netlify.app
    If you have any questions or suggestions, I’d be grateful to hear from you. ↩

  3. This solution is entirely my own work. It was developed using R version 4.4.1 (2024-06-14 ucrt). ↩