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Language/Type: PHP arrays traversals

Write a function named longest_sorted_sequence that accepts an array of integers as a parameter and that returns the length of the longest sorted (non-decreasing) sequence of integers in the array.

For example, if a variable named $arr stores the following values:

$arr = [3, 8, 10, 1, 9, 14, -3, 0, 14, 207, 56, 98, 12];

then the call of longest_sorted_sequence($arr) should return 4 because the longest sorted sequence in the array has four values in it (the sequence -3, 0, 14, 207). Note that sorted means non-decreasing, which means that the sequence could contain duplicates. For example, if the array stores the following values:

$arr = [17, 42, 3, 5, 5, 5, 8, 2, 4, 6, 1, 19];

Then the function would return 5 for the length of the longest sequence (3, 5, 5, 5, 8). Your function should return 0 if passed an empty array, and should return 1 if passed an array that is entirely in decreasing order or contains only one element.


  • You may not use any auxiliary data structures (arrays, strings, etc.) to solve this problem.
  • Your function should not modify the array that is passed in.
Function: Write a PHP function as described, not a complete program.

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