题目描述 Each of Farmer John's N (4 <= N <= 16) cows has a unique serial number S_i (1 <= S_i <= 25,000). The cows are so proud of it that each one now wears her number in a gangsta manner engraved in large letters on a gold plate hung around her…

原题地址 观察数据范围:4 ≤ N ≤ 16. 很明显,这是一道状压DP. 定义:dp[i][j]表示队尾为奶牛i,当前含奶牛的状态为j,共有多少组符合条件的队伍. 代码实现如下: #include <bits/stdc++.h> using namespace std; #define LL long long #define rep(i, a, b) for (register int i = a; i <= b; i++) ; int n, m; LL ans = ; int a[…

嘟嘟嘟 一看n那么小,那一定是状压dp了(表示从没写过,慌). 首先dp[i][j](i 是一个二进制数,第x位为1代表选了第x头牛),表示 i 这个状态最后一头牛是第 j 头牛时的方案数. 然后当 j 被选上时,即 if(i & (1 << (j - 1)))时,我们在枚举倒数第二头牛p,也是当他存在时,且满足 abs(s[p] - s[j]) > k时,dp[i][j] += dp[i ^ (1 << (j - 1))][p],因为最后一头牛为p时,j 还没有被选…

P2915 [USACO08NOV]奶牛混合起来Mixed Up Cows 题意: 给定一个长\(N\)的序列,求满足任意两个相邻元素之间的绝对值之差不超过\(K\)的这个序列的排列有多少个? 范围: \(0<=n<=16,0<=序列元素<=25000,0<=k<=3400\) 统计次数一般是递推干的事情,但是我们发现,这个递推并没有一个很明显的顺序关系,并不可以说前几个转移到下一个之类的. 看看数据这么小,一般都是状压干的事情了. 我们可以按照规模进行递推,即一个大小…

P2915 [USACO08NOV]奶牛混合起来Mixed Up Cows 题目描述 Each of Farmer John's N (4 <= N <= 16) cows has a unique serial number S_i (1 <= S_i <= 25,000). The cows are so proud of it that each one now wears her number in a gangsta manner engraved in large le…

P2915 [USACO08NOV]奶牛混合起来Mixed Up Cows 题目描述 Each of Farmer John's N (4 <= N <= 16) cows has a unique serial number S_i (1 <= S_i <= 25,000). The cows are so proud of it that each one now wears her number in a gangsta manner engraved in large le…

题目描述 Each of Farmer John's N (4 <= N <= 16) cows has a unique serial number S_i (1 <= S_i <= 25,000). The cows are so proud of it that each one now wears her number in a gangsta manner engraved in large letters on a gold plate hung around her…

题目描述 Each of Farmer John's N (4 <= N <= 16) cows has a unique serial number S_i (1 <= S_i <= 25,000). The cows are so proud of it that each one now wears her number in a gangsta manner engraved in large letters on a gold plate hung around her…

题目描述 Each of Farmer John's N (4 <= N <= 16) cows has a unique serial number S_i (1 <= S_i <= 25,000). The cows are so proud of it that each one now wears her number in a gangsta manner engraved in large letters on a gold plate hung around her…

题目描述 Each of Farmer John's N (4 <= N <= 16) cows has a unique serial number S_i (1 <= S_i <= 25,000). The cows are so proud of it that each one now wears her number in a gangsta manner engraved in large letters on a gold plate hung around her…