如果将$x$和$y$都离散,那么删除的点的$x_{i}$和$y_{i}$必然都组成了一个完整的区间(包括过程中) 将所有点按$x$排序,再令$f[i][j][0/1]$表示当删除完区间$[i,j]$且位于点$i$/点$j$时答案(若无法删除记为$\infty$),转移考虑下一次删除的点($i-1$或$j+1$)是否可行 (这里的答案指在这个状态后删除尽量多的点所需最短时间,因此最终答案为$f[i][i][0/1]$,初始状态不易确定,可以记忆化搜索来做,当无法转移即为0) 根据上面的结论,记$m…

UVA - 11134 Fabled Rooks We would like to place n rooks, 1 ≤ n ≤ 5000, on a n × n board subject to the following restrictions The i-th rook can only be placed within the rectan- gle given by its left-upper corner (xli,yli) and its right- lower corner…

http://www.lightoj.com/volume_showproblem.php?problem=1005        PDF (English) Statistics Forum Time Limit: 1 second(s) Memory Limit: 32 MB A rook is a piece used in the game of chess which is played on a board of square grids. A rook can only move…

问题来源:刘汝佳<算法竞赛入门经典--训练指南> P81: 问题描述:你的任务是在n*n(1<=n<=5000)的棋盘上放n辆车,使得任意两辆车不相互攻击,且第i辆车在一个给定的矩形R之内. 问题分析:1.题中最关键的一点是每辆车的x坐标和y坐标可以分开考虑(他们互不影响),不然会变得很复杂,则题目变成两次区间选点问题:使得每辆车在给定的范围内选一个点,任何两辆车不能选同一个点.  2.本题另外一个关键点是贪心法的选择,贪心方法:对所有点的区间,按右端点从小到大排序:每次在一个区间…

We would like to place n rooks, 1 n 5000, on a n nboard subject to the following restrictions• The i-th rook can only be placed within the rectan-gle given by its left-upper corner (xli; yli) and its right-lower corner (xri; yri), where 1 i n, 1 xli…

Problem F: Fabled Rooks We would like to place n rooks, 1 ≤ n ≤ 5000, on a n×n board subject to the following restrictions The i-th rook can only be placed within the rectangle given by its left-upper corner (xli, yli) and its right-lower corner (xri…

We would like to place  n  rooks, 1 ≤  n  ≤ 5000, on a  n×n  board subject to the following restrictions The i-th rook can only be placed within the rectangle given by its left-upper corner (xli, yli) and its right-lower corner (xri, yri), where 1 ≤ …

Problem F: Fabled Rooks We would like to place n rooks, 1 ≤ n ≤ 5000, on a n×n board subject to the following restrictions The i-th rook can only be placed within the rectangle given by its left-upper corner (xli, yli) and its right-lower corner (xri…

题目链接:uva 11134 - Fabled Rooks 题目大意:给出n,表示要在n*n的矩阵上放置n个车,并且保证第i辆车在第i个区间上,每个区间给出左上角和右小角的坐标.另要求任意两个车之间不能互相攻击. 解题思路:因为要保证说每两个车之间不能互相攻击,那么即任意行列都不能摆放两个以上的车,转而言之可以看成是将每一行或列分配给每辆车.如果行和列和起来考虑的话复杂度太高了,但是行和列的分配又互相不影响,所以可以分开讨论. 即对于一个区间[xl,xr],要分配一个x给它,做法和uva 142…

1005 - Rooks   PDF (English) Statistics Forum Time Limit: 1 second(s) Memory Limit: 32 MB A rook is a piece used in the game of chess which is played on a board of square grids. A rook can only move vertically or horizontally from its current positio…