of incorrect estimates. Method Marzullo's algorithm begins by preparing a table of the sources, sorting it and then searching (efficiently) for the intersections of intervals. For each source there is a range [c−r,c+r] defined by c ± r. For each range the table will have two tuples of the form . One tuple will represent the beginning of the range, marked with type −1 as and the other will represent the end with type +1 as . The description of the algorithm uses the following variables: best (largest number of overlapping intervals found), cnt (current number of overlapping intervals), beststart and bestend (the beginning and end of best interval found so far), i (an index), and the table of tuples. Build the table of tuples. Sort the table by the offset. (If two tuples with the same offset but opposite types exist, indicating that one interval ends just as another begins, then a method of deciding which comes first is necessary. Such an occurrence can be considered an overlap with no duration, which can be found by the algorithm by putting type −1 before type +1. If such pathological overlaps are considered objectionable they can be avoided by putting type +1 before −1 in this case.) [initialize] best=0 cnt=0 [loop] go through each tuple in the table in ascending order [current number of overlapping intervals] cnt=cnt−type[i] if cnt>best then best=cnt beststart=offset[i] bestend=offset[i+1] commentary: the next tuple, at [i+1], will either be an end of an interval (type=+1) in which case it ends this best interval, or it will be a beginning of an interval (type=−1) and in the next step will replace best. ambiguity: unspecified is what to do if best=cnt. This is a condition of a tie for greatest overlap. The decision can either be made to take the smaller of bestend−beststart and offset[i+1]−offset[i] or just take an arbitrary one of the two equally good entries. This decision is relevant only when type[i+1]=+1. [end loop] return [beststart,bestend] as optimal interval. The number of false sources (ones which do not overlap the optimal interval returned) is the number of sources minus the value of best. Efficiency Marzullo's algorithm is efficient in both space and time. The asymptotic space usage is O(n), where n is the number of sources. In considering the asymptotic time requirement the algorithm can be considered to consist of building the table, sorting it and searching it.