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Language/Type: PHP arrays traversals

Write a function named count_unique that accepts an array of integers as a parameter and returns a count of the number of unique values that occur in the array. If the array contains multiple occurrences of the same element value, only one of those occurrences should count toward your total.

For example, if an array named $numbers stores [7, 7, 2, 2, 1, 2, 2, 7], the call of count_unique($numbers) should return 3 because there are 3 unique values: 7, 2, and 1.


  • In solving this problem, do not create any other data structures such as arrays, strings, etc., though you may create as many simple variables (e.g. integers) as you like.
  • Do not modify the array passed to your function as the parameter, such as by sorting or rearranging its element values.
Function: Write a PHP function as described, not a complete program.

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