Limit Element Occurrences in Sorted Array

You are given an integer array nums arranged in non-decreasing order. Your task is to modify the array in-place so that each unique value appears at most twice, while preserving the original relative ordering of elements.

Since certain programming languages do not allow resizing arrays, the valid result should occupy the first k positions of the original array. The function must return the value k, representing the count of elements in the final processed array.

Important: Only the first k elements of the modified array will be evaluated. Any values beyond position k are considered irrelevant and will not affect the correctness of your solution.

The solution must operate directly on the input array without allocating a separate array for output. Your algorithm should use only O(1) auxiliary space beyond the input array itself.

Evaluation Criteria:

The validation system will verify your solution as follows:

int[] nums = [...]; // Input array
int[] expectedResult = [...]; // Expected array with correct length

int k = limitOccurrences(nums); // Your implementation

assert k == expectedResult.length;
for (int i = 0; i < k; i++) {
    assert nums[i] == expectedResult[i];
}

Your solution passes if all assertions succeed.

nums = [1,1,1,2,2,3]

k = 5, nums = [1,1,2,2,3,_]

nums = [0,0,1,1,1,1,2,3,3]

k = 7, nums = [0,0,1,1,2,3,3,_,_]

nums = [1,1,2,2,3,3]

k = 6, nums = [1,1,2,2,3,3]