how can I simplify this code?

is there any way to simplify this code? any help would be appreciated thanks.

function [idx, pairs_checked, scan_indices] = two_ended_search_1(x, target)
% TWO_ENDED_SEARCH  Bidirectional scan from array ends toward center (arrays-only).

    n = length(x);

    % --- Edge case: empty array ---
    if n == 0
        idx = -1;
        pairs_checked = zeros(0,2);
        scan_indices  = zeros(1,0);
        return;
    end

    % --- Preallocate with conservative sizes ---
    maxIters = ceil(n/2);
    pairs_checked = zeros(maxIters, 2);
    scan_indices  = zeros(1, 2*maxIters);  % at most two comparisons per iter

    L = 1; R = n;
    idx = -1;

    pairCount = 0;
    scanCount = 0;

    while L <= R
        % Record pair at start of iteration
        pairCount = pairCount + 1;
        pairs_checked(pairCount, :) = [L, R];

        % Compare left
        scanCount = scanCount + 1;
        scan_indices(scanCount) = L;
        if x(L) == target
            idx = L;
            break;
        end

        % If middle element already checked, stop (avoid duplicate compare)
        if L == R
            break;
        end

        % Compare right
        scanCount = scanCount + 1;
        scan_indices(scanCount) = R;
        if x(R) == target
            idx = R;
            break;
        end

        % Move pointers inward
        L = L + 1;
        R = R - 1;
    end

    % Trim prealloc arrays to actual sizes
    pairs_checked = pairs_checked(1:pairCount, :);
    scan_indices  = scan_indices(1:scanCount);

end


x = [5, 2, 3, 1, 9, 7, 9, 4, 8];
target = 4;

[idx, pairs_checked, scan_indices] = two_ended_search_1(x, target)

idx = 8

pairs_checked = 2×2

1 9 2 8

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scan_indices = 1×4

1 9 2 8

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Answer 1

[Chuguang Pan]

function [idx,pairs,scan] = Two_Ended_Search_2(x,target)
    idx = find(x==target);
    n = length(x);
    LR = min(idx-1,n-idx);
    pairsL = 1:(LR+1);
    pairsR = n:-1:n-LR;
    pairs = [pairsL.' pairsR.'];
    scan = reshape(pairs.',1,[]);
end

X =  [5, 2, 3, 1, 9, 7, 9, 4, 8];
target = 4;
[Idx,Paris,Scan] = Two_Ended_Search_2(X,target)

Idx = 8

Paris = 2×2

1 9 2 8

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Scan = 1×4

1 9 2 8

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