River Crossing 时间限制:1000 ms  |  内存限制:65535 KB 难度:4 描述 Afandi is herding N sheep across the expanses of grassland  when he finds himself blocked by a river. A single raft is available for transportation. Afandi knows that he must ride on the raft for…

1617: [Usaco2008 Mar]River Crossing渡河问题 Time Limit: 5 Sec  Memory Limit: 64 MBSubmit: 654  Solved: 466[Submit][Status] Description Farmer John以及他的N(1 <= N <= 2,500)头奶牛打算过一条河,但他们所有的渡河工具,仅仅是一个木筏. 由于奶牛不会划船,在整个渡河过程中,FJ必须始终在木筏上.在这个基础上,木筏上的奶牛数目每增加1,FJ把木筏划…

dp[ i ] = max( dp[ j ] + sum( M_1 ~ M_( i - j ) ) + M , sum( M_1 ~ M_i ) ) ( 1 <= j < i )  表示运送 i 只羊的最少时间 , 转移很显然. T T 我自己第一次写时 , dp多带了个k表示第几次送牛过河 , 可是这并没有什么卵用..还 TLE 了... ------------------------------------------------------------------------- #in…

题目 1617: [Usaco2008 Mar]River Crossing渡河问题 Time Limit: 5 Sec  Memory Limit: 64 MB Description Farmer John以及他的N(1 <= N <= 2,500)头奶牛打算过一条河,但他们所有的渡河工具,仅仅是一个木筏. 由于奶牛不会划船,在整个渡河过程中,FJ必须始终在木筏上.在这个基础上,木筏上的奶牛数目每增加1,FJ把木筏划到对岸就得花更多的时间. 当FJ一个人坐在木筏上,他把木筏划到对岸需要M(…

1488: River Crossing Time Limit: 1 Sec  Memory Limit: 128 MB Submit: 83  Solved: 42 SubmitStatusWeb Board Description Afandi is herding N sheep across the expanses of grassland  when he finds himself blocked by a river. A single raft is available for…

P2904 [USACO08MAR]跨河River Crossing 显然的dp 设$f[i]$表示运走$i$头奶牛,木筏停在未过河奶牛一侧所用的最小代价 $s[i]$表示一次运$i$头奶牛到对面的代价 我们枚举上次运走了$j$头,显然$f[i]=min(f[i],f[i-j]+s[j]+s[0])$(注意自己要划回来) 最后不用划回来,减去一个$s[0]$即可 end. #include<iostream> #include<cstdio> #include<cstring…

1617: [Usaco2008 Mar]River Crossing渡河问题 Time Limit: 5 Sec  Memory Limit: 64 MBSubmit: 1219  Solved: 895[Submit][Status][Discuss] Description Farmer John以及他的N(1 <= N <= 2,500)头奶牛打算过一条河,但他们所有的渡河工具,仅仅是一个木筏. 由于奶牛不会划船,在整个渡河过程中,FJ必须始终在木筏上.在这个基础上,木筏上的奶牛数目每…

River Crossing渡河问题 bzoj-1617 Usaco-2008 Mar 题目大意:题目链接. 注释:略. 想法:zcs0724出考试题的时候并没有发现这题我做过... 先把m求前缀和,存在bfr数组里. 然后就可以dp了: 状态:dp[i]表示送完前i头牛的最小时间. 转移:$dp[i]=min\{dp[j]+bfr[i-j]\}$; 最后,附上丑陋的代码... ... #include <iostream> #include <cstdio> #include &…

洛谷 P2904 [USACO08MAR]跨河River Crossing https://www.luogu.org/problem/P2904 JDOJ 2574: USACO 2008 Mar Silver 3.River Crossing https://neooj.com:8082/oldoj/problem.php?id=2574 题目描述 Farmer John is herding his N cows (1 <= N <= 2,500) across the expanses…

题目描述 Farmer John is herding his N cows (1 <= N <= 2,500) across the expanses of his farm when he finds himself blocked by a river. A single raft is available for transportation. FJ knows that he must ride on the raft for all crossings and that that…