摘要：
Recently, iSea went to an ancient country. For such a long time, it was the most wealthy and powerful kingdom in the world. As a result, the p... 阅读全文
摘要：
设2n张牌分别标记为1, 2, …, n, n+1, …, 2n，初始时这2n张牌按其标号从小到大排列。经一次洗牌后，原来的排列顺序变成n+1, 1, n+2, 2, …, 2n, n。即前n张牌被放到偶数位置2, 4, …, 2n，而后n张牌被放到奇数位置1, 3, …, 2n-1... 阅读全文