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JạþTS×¬MḢ


Uses 1-based indexing. Try it online! or verify all test cases.

How it works

JạþTS×¬MḢ  Main link. Argument: A (array of Booleans)

J          Yield all indices of A.
   T       Yield all truthy indices of A.
 ạþ        Compute the table of absolute differences.
    S      Compute the sums of all columns.
           For each index, this yields the sum of all distances to occupied stalls.
     ×¬    Multiply each sum by the logical NOT of the corresponding Boolean in A.
           This zeroes sums that correspond to occupied stalls.
       M   Maximal; yield an array of all indices of maximal sums.
        Ḣ  Head; extract the first index.