摘要：
JAVA： int an = 0; public final int countArrangement(int N) { search(N, new HashSet<Integer>(), 0); return an; } private final void search(int n, Set<I 阅读全文
摘要：
JAVA 分治： public final int mincostTickets(int[] days, int[] costs) { return minCost(days, costs, days.length - 1, new int[days.length]); } private fina 阅读全文