footrule การใช้

• "Metric martyrs " site, http : / / www . footrule . org / Martyr2 . htm
• Other measures of ( pre-) sortedness include the minimum number of elements that can be deleted from the sequence to yield a fully sorted sequence, the number and lengths of sorted " runs " within the sequence, the Spearman footrule ( sum of distances of each element from its sorted position ), and the smallest number of exchanges needed to sort the sequence.