题目链接:http://poj.org/problem?id=3662 Telephone Lines Time Limit: 1000MS   Memory Limit: 65536K Total Submissions: 8248   Accepted: 2977 Description Farmer John wants to set up a telephone line at his farm. Unfortunately, the phone company is uncoopera…

目录 题面 题目链接 题目描述 输入输出格式 输入格式 输出格式 输入输出样例 输入样例 输出样例 说明 思路 AC代码 题面 题目链接 P1948 [USACO08JAN]电话线Telephone Lines 题目描述 Farmer John wants to set up a telephone line at his farm. Unfortunately, the phone company is uncooperative, so he needs to pay for some of…

Farmer John wants to set up a telephone line at his farm. Unfortunately, the phone company is uncooperative, so he needs to pay for some of the cables required to connect his farm to the phone system. There are N (1 ≤ N ≤ 1,000) forlorn telephone pol…

POJ3662 Telephone Lines 题目大意:要在顶点1到顶点n之间建一条路径,假设这条路径有m条边,其中有k条边是免费的,剩余m-k条边是要收费的, 求这m-k条边中花费最大的一条边的最小花费. 让m条边中原本花费最大的k条边成为免费的边,则这时m-k条边中花费最大的一条边的花费最小. 二分枚举m-k条边中花费最大的一条边的最小花费x,dijkstra求最短路径时,将花费大于x的边的花费设为1(花费为INF的边不变),花费小于等于x的边设为 0,则d[v-1]中返回的就是花费大于x…

http://poj.org/problem?id=3662 Telephone Lines Time Limit: 1000MS   Memory Limit: 65536K Total Submissions:9310   Accepted: 3374 Description Farmer John wants to set up a telephone line at his farm. Unfortunately, the phone company is uncooperative,…

P1948 [USACO08JAN]电话线Telephone Lines 题意 题目描述 Farmer John wants to set up a telephone line at his farm. Unfortunately, the phone company is uncooperative, so he needs to pay for some of the cables required to connect his farm to the phone system. Ther…

链接:洛谷 POJ 题目描述 Farmer John wants to set up a telephone line at his farm. Unfortunately, the phone company is uncooperative, so he needs to pay for some of the cables required to connect his farm to the phone system. There are N (1 ≤ N ≤ 1,000) forlor…

Description Farmer John打算将电话线引到自己的农场,但电信公司并不打算为他提供免费服务.于是,FJ必须为此向电信公司支付一定的费用. FJ的农场周围分布着N(1 <= N <= 1,000)根按1..N顺次编号的废弃的电话线杆,任意两根电话线杆间都没有电话线相连.一共P(1 <= P <= 10,000)对电话线杆间可以拉电话线,其余的那些由于隔得太远而无法被连接. 第i对电话线杆的两个端点分别为A_i.B_i,它们间的距离为 L_i (1 <= L_i…

Description FarmerJohn打算将电话线引到自己的农场,但电信公司并不打算为他提供免费服务.于是,FJ必须为此向电信公司 支付一定的费用.FJ的农场周围分布着N(1<=N<=1,000)根按1..N顺次编号的废弃的电话线杆,任意两根电话线杆间 都没有电话线相连.一共P(1<=P<=10,000)对电话线杆间可以拉电话线,其余的那些由于隔得太远而无法被连接. 第i对电话线杆的两个端点分别为A_i.B_i,它们间的距离为L_i(1<=L_i<=1,000,0…

题意: 给一个2e4带正边权的图,可以免费k个边,一条路径的花费为路径上边权最大值,问你1到n的最小花费 思路: 对于一个x,我们如果将大于等于x的边权全部免费,那么至少需要免费的边的数量就是 “设大于等于x的边权的边长为1,其余为0,起点到终点的最短路” 然后如果这个得到的最短路,也就是我们所需要免费的边数小于等于k的话,就可以满足题意了(check) 思考一下可以发现对于任何条件,都存在某一个p,当x取[p, inf]的任意值时,都是可以满足题意的 于是我们就可以二分x并check了 得到p…

Description Farmer John打算将电话线引到自己的农场,但电信公司并不打算为他提供免费服务.于是,FJ必须为此向电信公司支付一定的费用. FJ的农场周围分布着N(1 <= N <= 1,000)根按1..N顺次编号的废弃的电话线杆,任意两根电话线杆间都没有电话线相连.一共P(1 <= P <= 10,000)对电话线杆间可以拉电话线,其余的那些由于隔得太远而无法被连接. 第i对电话线杆的两个端点分别为A_i.B_i,它们间的距离为 L_i (1 <= L_i…

题目传送门 题意:有n个点, p条路,每条道路有个花费Li, 然后现在要建一条1-n的路线,然后可以选k条道路免费, 然后可以在剩下的道路中选择价格最高的边支付费用, 求这个答案最小. 题解: 二分答案. 每次check过程中, 一条边的花费 <= mid 则 路径长度为0,否者路径长度为1.然后 求 到n的点之后长度<=k. 然后就是bfs的过程中. 如果这条边是0, 那么从前入队, 否者从后入队. 代码: #include<cstdio> #include<algorit…

题目描述 Farmer John打算将电话线引到自己的农场,但电信公司并不打算为他提供免费服务.于是,FJ必须为此向电信公司支付一定的费用. FJ的农场周围分布着N(1 <= N <= 1,000)根按1..N顺次编号的废弃的电话线杆,任意两根电话线杆间都没有电话线相连.一共P(1 <= P <= 10,000)对电话线杆间可以拉电话线,其余的那些由于隔得太远而无法被连接. 第i对电话线杆的两个端点分别为A_i.B_i,它们间的距离为 L_i (1 <= L_i <=…

思路: 二分+最短路.最短路也可以用来计算从a到达b所需的边权不超过x的边的数量. 实现: #include <cstdio> #include <cmath> #include <queue> #include <cstring> using namespace std; const int INF = 0x3f3f3f3f; ; int G[MAXN][MAXN], d[MAXN]; bool in[MAXN]; int n, p, k; int spf…

题意:有N个独立点,其中有P对可用电缆相连的点,要使点1与点N连通,在K条电缆免费的情况下,问剩下的电缆中,长度最大的电缆可能的最小值为多少. 分析: 1.二分临界线(符合的情况的点在右边),找可能的最小值,假设为mid. 2.将大于mid的边变为1,小于等于mid的边变为0(表示这些边由自己承包),由此算出1~N的最短路长度为x.x即为所用的大于mid的电缆个数. 3.若x<=K,则符合情况,但是想让所用的免费电缆条数x更多,所以让mid更小一些,这样自己承包的边也减少,x将更大,即r = m…

Telephone Lines Time Limit: 1000MS   Memory Limit: 65536K Total Submissions: 7214   Accepted: 2638 Description Farmer John wants to set up a telephone line at his farm. Unfortunately, the phone company is uncooperative, so he needs to pay for some of…

Telephone Lines bzoj-1614 Usaco-2007Jan 题目大意:给你一个n个点m条边的带边权无向图,求最短路.可以选取k条边免费. 注释:$1\le n\le 10^3$,$1\le m\le 10^5$ 想法:一眼分层图最短路啊! 我都想出来了就上网查一下题解吧 卧槽??二分+spfa?? 其实这个题不用分层图 我们二分答案,二分出最大值,然后将图中所有比mid大的边设为1,小的设为0,然后跑最短路.如果最短路的值比k大,说明最大值一定比二分的mid大.因为我的最短路…

[Usaco2007 Jan]Telephone Lines架设电话线 Description FarmerJohn打算将电话线引到自己的农场,但电信公司并不打算为他提供免费服务.于是,FJ必须为此向电信公司支付一定的费用.FJ的农场周围分布着N(1<=N<=1,000)根按1..N顺次编号的废弃的电话线杆,任意两根电话线杆间都没有电话线相连.一共P(1<=P<=10,000)对电话线杆间可以拉电话线,其余的那些由于隔得太远而无法被连接. 第i对电话线杆的两个端点分别为A_i.B_…

Telephone Lines Time Limit: 1000MS   Memory Limit: 65536K Total Submissions: 6973   Accepted: 2554 Description Farmer John wants to set up a telephone line at his farm. Unfortunately, the phone company is uncooperative, so he needs to pay for some of…

Telephone Lines Time Limit: 1000MS   Memory Limit: 65536K Total Submissions: 7115   Accepted: 2603 Description Farmer John wants to set up a telephone line at his farm. Unfortunately, the phone company is uncooperative, so he needs to pay for some of…

Telephone Lines Time Limit: 1000MS Memory Limit: 65536K Total Submissions: 7978 Accepted: 2885 Description Farmer John wants to set up a telephone line at his farm. Unfortunately, the phone company is uncooperative, so he needs to pay for some of the…

洛谷 P1948 [USACO08JAN]电话线Telephone Lines https://www.luogu.org/problem/P1948 JDOJ 2556: USACO 2008 Jan Silver 3.Telephone Lines https://neooj.com/oldoj/problem.php?id=2556 题目描述 Farmer John wants to set up a telephone line at his farm. Unfortunately, t…

P1948 [USACO08JAN]电话线Telephone Lines 题目描述 Farmer John wants to set up a telephone line at his farm. Unfortunately, the phone company is uncooperative, so he needs to pay for some of the cables required to connect his farm to the phone system. There a…

1614: [Usaco2007 Jan]Telephone Lines架设电话线 Time Limit: 5 Sec  Memory Limit: 64 MBSubmit: 892  Solved: 399[Submit][Status] Description Farmer John打算将电话线引到自己的农场,但电信公司并不打算为他提供免费服务.于是,FJ必须为此向电信公司支付一定的费用. FJ的农场周围分布着N(1 <= N <= 1,000)根按1..N顺次编号的废弃的电话线杆,任意两…

题目 1614: [Usaco2007 Jan]Telephone Lines架设电话线 Time Limit: 5 Sec  Memory Limit: 64 MB Description Farmer John打算将电话线引到自己的农场,但电信公司并不打算为他提供免费服务.于是,FJ必须为此向电信公司支付一定的费用. FJ的农场周围分布着N(1 <= N <= 1,000)根按1..N顺次编号的废弃的电话线杆,任意两根电话线杆间都没有电话线相连.一共P(1 <= P <= 10…

Telephone Lines Time Limit: 1000MS   Memory Limit: 65536K Total Submissions: 6785   Accepted: 2498 Description Farmer John wants to set up a telephone line at his farm. Unfortunately, the phone company is uncooperative, so he needs to pay for some of…

P1948 [USACO08JAN]电话线Telephone Lines 题目描述 Farmer John wants to set up a telephone line at his farm. Unfortunately, the phone company is uncooperative, so he needs to pay for some of the cables required to connect his farm to the phone system. There a…

Telephone Lines Time Limit: 1000MS   Memory Limit: 65536K Total Submissions: 5696   Accepted: 2071 Description Farmer John wants to set up a telephone line at his farm. Unfortunately, the phone company is uncooperative, so he needs to pay for some of…

题目链接 题意 有\(n\)个牛棚,每个牛棚初始有\(a_i\)头牛,最后能容纳\(b_i\)头牛.有\(m\)条道路,边权为走这段路所需花费的时间.问最少需要多少时间能让所有的牛都有牛棚可待? 思路 二分 因为问题具有单调性,因此考虑二分时间,\(check\)是否满足条件. 满足条件指什么呢? 是指所有的牛都有牛棚可待. 是指所有的牛都顺利地从某一个牛棚移动到了另一个合法的牛棚(或者不移动),而这个移动是在限定的时间范围内的. 建图 首先拆点,将牛棚拆成 初始牛棚 与 终态牛棚. 在 源点…

P1462 通往奥格瑞玛的道路 题面 题目背景 在艾泽拉斯大陆上有一位名叫歪嘴哦的神奇术士,他是部落的中坚力量 有一天他醒来后发现自己居然到了联盟的主城暴风城 在被众多联盟的士兵攻击后,他决定逃回自己的家乡奥格瑞玛 题目描述 在艾泽拉斯,有 \(n\) 个城市.编号为 \(1,2,3,...,n\) . 城市之间有 \(m\) 条双向的公路,连接着两个城市,从某个城市到另一个城市,会遭到联盟的攻击,进而损失一定的血量. 每次经过一个城市,都会被收取一定的过路费(包括起点和终点).路上并没有收费站…