If B[i]=B[i+1], it can only be deduced that the width for one of the subintervals A[j+1]-A[j]>1/64. But which subinterval the random number a resides is independent of the width of the subinterval, am i right?
Actually the matrix A is a known quantity, which determines how the interval [0,1) is divided into subintervals, the widths of which might not be the same. And the random number a is the "true" variable.
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