Time Limit: 2000/1000 MS (Java/Others)    Memory Limit: 327680/327680 K (Java/Others) Total Submission(s): 4619    Accepted Submission(s): 846 Problem Description "Across the Great Wall, we can reach every corner in the world!" Now the citizens…

题目连接:hdu 3669 Cross the Wall 题意: 现在有一面无限大的墙,现在有n个人,每个人都能看成一个矩形,宽是w,高是h,现在这n个人要通过这面墙,现在只能让你挖k个洞,每个洞不能重叠,每个洞需要消耗你挖的w*h,现在问你最小消耗多少. 题解: 设dp[i][j]为前j个人挖i个洞的最小消耗. 首先我们先将每个人按w排序,我们可以发现,排序后的h是递减的,因为如果不是递减的,可以把那个点消掉,因为w[k]<w[j]&&h[k]<h[j]的话,那么第k个人就可…

题目大意 给定 \(N\) 个矩形的宽和高, \((h_1, w_1), (h_2, w_2), \dots, (h_n w_n)\) . 现需要确定 \(k\) (\(k \le K\), \(K\) 给定) 个矩形 \((H_i, W_i)\) , 使得 \(\forall i \ (1\le i\le N), \exists j,\ s.t.\ H_j \ge h_i\) 且 \(W_j \ge w_i\), 此时称这后 \(k\) 个矩形覆盖前 \(N\) 个矩形, 代价为 \(\sum…

题目链接:http://acm.hdu.edu.cn/showproblem.php?pid=3669 题目大意:有n(n<=50000)个矩形,每个矩形都有高和宽,你可以在墙上最多挖k个洞使得可以通过,问你最小花费(所有挖的洞的h*w之和)是多少. 解题思路:先将所有矩形按宽从大到小,高从大到小,如果一个矩形宽和高都小于等于前面的矩形则肯定会被前面的矩形覆盖(完全放在前面的矩形里),那么这个矩形就可以删掉,因为不影响结果. 最后再倒序,使得宽从小到大,高从大到小,则状态转移方程为:dp[i][…

贪心思想,$dp$,斜率优化. 首先将人按照$w$从大到小排序,如果$w$一样,按$h$从大到小排.这样一来,某位置之后,比该位置$h$小的都是不需要考虑的. 因此,形成了如下图所示的结果: 即第一个人最宽,但是最矮,最后一个人最瘦但是最高. 接下来考虑这些人怎么挖洞.还是上图,如果第一个人和第三个人都是从同一个洞里通过的,那么中间那个肯定也可以从那个洞里通过的. 也就是说一定是连续的一段人从同一个洞通过,接下来的任务就是如何将这些人分段. 设$dp[i][j]$表示前$i$个人分成了$j$段的…

首先要感谢叉姐的指导Orz 这一类问题的DP方程都有如下形式 dp[i] = w(i) + max/min(a(i)*b(j) + c(j)) ( 0 <= j < i ) 其中,b, c均为j的单调函数.通常情况下a(i)也是单调的,a(i)不单调时就只能二分查找了. 这里讲一下当c(j)单调递增,b(j)单调递减,原方程求min的情况 对于同一j,b(j),c(j)为常数,而a(i)为变量,令y = b(j) * x + c(j),则y为线性函数 我们把( 0 <= j < i…

问题分析 首先,如果一个人的\(w\)和\(h\)均小于另一个人,那么这个人显然可以被省略.如果我们将剩下的人按\(w[i]\)递增排序,那么\(h[i]\)就是递减. 之后我们考虑DP. 我们设\(f[i][j]\)为到第\(i\)个人,打了\(j\)个洞的花费.于是我们可以得到如下DP过程: for( LL i = 1; i <= N; ++i ) F[ i ][ 1 ] = w[ i ] * h[ 1 ]; for( LL j = 2; j <= K; ++j ) for( LL i =…

        ID Origin Title   20 / 60 Problem A HDU 3507 Print Article   13 / 19 Problem B HDU 2829 Lawrence   1 / 5 Problem C HDU 4528 小明系列故事――捉迷藏   5 / 6 Problem D HDU 1300 Pearls   0 / 42 Problem E HDU 2993 MAX Average Problem   1 / 20 Problem F UVALi…

KUANGBIN带你飞 全专题整理 https://www.cnblogs.com/slzk/articles/7402292.html 专题一 简单搜索 POJ 1321 棋盘问题    //2019.3.18 POJ 2251 Dungeon Master POJ 3278 Catch That Cow  //4.8 POJ 3279 Fliptile POJ 1426 Find The Multiple  //4.8 POJ 3126 Prime Path POJ 3087 Shuffle…

(自己的理解:首先考虑单调队列,不行时考虑斜率,再不行就考虑不等式什么的东西) 当dp的状态转移方程dp[i]的状态i需要从前面(0~i-1)个状态找出最优子决策做转移时 我们常常需要双重循环 (一重循环跑状态 i,一重循环跑 i 的所有子状态)这样的时间复杂度是O(N^2)而 斜率优化或者四边形不等式优化后的DP 可以将时间复杂度缩减到O(N) O(N^2)可以优化到O(N) ,O(N^3)可以优化到O(N^2),依次类推 斜率优化DP和四边形不等式优化DP主要的原理就是利用斜率或者四边形不等…

Cross the Wall Time Limit: 2000/1000 MS (Java/Others)    Memory Limit: 327680/327680 K (Java/Others)Total Submission(s): 4479    Accepted Submission(s): 812 Problem Description “Across the Great Wall, we can reach every corner in the world!” Now the…

[kuangbin带你飞]专题1-23 专题一 简单搜索 POJ 1321 棋盘问题POJ 2251 Dungeon MasterPOJ 3278 Catch That CowPOJ 3279 FliptilePOJ 1426 Find The MultiplePOJ 3126 Prime PathPOJ 3087 Shuffle'm UpPOJ 3414 PotsFZU 2150 Fire GameUVA 11624 Fire!POJ 3984 迷宫问题HDU 1241 Oil Deposit…

专题一 简单搜索 POJ 1321 棋盘问题POJ 2251 Dungeon MasterPOJ 3278 Catch That CowPOJ 3279 FliptilePOJ 1426 Find The MultiplePOJ 3126 Prime PathPOJ 3087 Shuffle'm UpPOJ 3414 PotsFZU 2150 Fire GameUVA 11624 Fire!POJ 3984 迷宫问题HDU 1241 Oil DepositsHDU 1495 非常可乐HDU 26…

1.一个proxy的实现 http://blog.codingnow.com/2011/05/xtunnel.html 2.SOCK5 RFC http://www.faqs.org/rfcs/rfc1928.html…

题意:给你一个多边形的城堡(多个点),使用最短周长的城墙将这个城堡围起来并保证城墙的每个点到城堡上的每个点的距离都不小于l 题解:因为两点间的直线一定比折线短,所以这样做 先使用所有点求得一个凸包,接着凸包每条边外移l长度,再在每相邻两条线间画一个半径为l的圆弧(想一想为什么) 因为凸包上每个点与平移后对应点相连会垂直于凸包对应的边,所有圆弧的每个角与对应多边形的内角互补 又因为多边形外角和为360度,所有可以看做凸包多加一个半径为l的圆 #include<set> #include<m…

http://poj.org/problem?id=1113 答案是凸包周长+半径为l的圆的周长... 证明?这是个坑.. #include <cstdio> #include <cstring> #include <cmath> #include <string> #include <iostream> #include <algorithm> #include <queue> #include <set>…

Wall Time Limit: 1000MS Memory Limit: 10000K Total Submissions: 32360 Accepted: 10969 Description Once upon a time there was a greedy King who ordered his chief Architect to build a wall around the King's castle. The King was so greedy, that he would…

题目链接:http://acm.hdu.edu.cn/showproblem.php?pid=1348 Wall Time Limit: 2000/1000 MS (Java/Others)    Memory Limit: 65536/32768 K (Java/Others) Total Submission(s): 3386    Accepted Submission(s): 968 Problem Description Once upon a time there was a gre…

Wall Time Limit: 1000MS   Memory Limit: 10000K Total Submissions: 26286   Accepted: 8760 Description Once upon a time there was a greedy King who ordered his chief Architect to build a wall around the King's castle. The King was so greedy, that he wo…

[题目] Description Once upon a time there was a greedy King who ordered his chief Architect to build a wall around the King's castle. The King was so greedy, that he would not listen to his Architect's proposals to build a beautiful brick wall with a p…

Time Limit: 1000MS   Memory Limit: 10000K Total Submissions: 27110   Accepted: 9045 Description Once upon a time there was a greedy King who ordered his chief Architect to build a wall around the King's castle. The King was so greedy, that he would n…

Wall Time Limit: 2000/1000 MS (Java/Others)    Memory Limit: 65536/32768 K (Java/Others) Total Submission(s): 3779    Accepted Submission(s): 1066 Problem Description Once upon a time there was a greedy King who ordered his chief Architect to build a…

传送门: POJ:点击打开链接 HDU:点击打开链接 以下是POJ上的题: Wall Time Limit: 1000MS   Memory Limit: 10000K Total Submissions: 29121   Accepted: 9746 Description Once upon a time there was a greedy King who ordered his chief Architect to build a wall around the King's cast…

There is a brick wall in front of you. The wall is rectangular and has several rows of bricks.The bricks have the same height but different width. You want to draw a vertical line from the top to the bottom and cross the least bricks.The brick wall i…

Description Once upon a time there was a greedy King who ordered his chief Architect to build a wall around the King's castle. The King was so greedy, that he would not listen to his Architect's proposals to build a beautiful brick wall with a perfec…

There is a brick wall in front of you. The wall is rectangular and has several rows of bricks. The bricks have the same height but different width. You want to draw a vertical line from the top to the bottom and cross the leastbricks. The brick wall…

There is a brick wall in front of you. The wall is rectangular and has several rows of bricks. The bricks have the same height but different width. You want to draw a vertical line from the top to the bottom and cross the leastbricks. The brick wall…

Wall Time Limit: 1000MS Memory Limit: 10000K Description Once upon a time there was a greedy King who ordered his chief Architect to build a wall around the King's castle. The King was so greedy, that he would not listen to his Architect's proposals…

［抄题］: There is a brick wall in front of you. The wall is rectangular and has several rows of bricks. The bricks have the same height but different width. You want to draw a vertical line from the top to the bottom and cross the least bricks. The bric…

Description Once upon a time there was a greedy King who ordered his chief Architect to build a wall around the King's castle. The King was so greedy, that he would not listen to his Architect's proposals to build a beautiful brick wall with a perfec…