约瑟夫环是一个数学的应用问题：已知n个人（以编号1，2，3...n分别表示）围坐在一张圆桌周围。从编号为k的人开始报数，数到m的那个人出列；他的下一个人又从1开始报数，数到m的那个人又出列；依此规律重复下去，直到圆桌周围的人全部出列。-Josephus is the application of a mathematical problem: Given n individuals (with numbers 1,2,3 ... n, respectively) sitting around a round table. From the number of people reported a few k, m is the number of out of that person　his next and from one individual to start off, count to m that another person out　so the law of repeated until the round table were all out of the column.