带来两题贪心算法的题. 1.给定长度为N的字符串S,要构造一个长度为N的字符串T.起初,T是一个空串,随后反复进行下面两个操作:1.从S的头部删除一个字符,加到T的尾部.2.从S的尾部删除一个字符,加到T的尾部.求你任意采取这两个步骤后能得到的最小字符串T 2.直线上有N个点,点i的位置是xi,这N个点中选择若干个做上标记,对于每个点,在他们距离为R的区域内必须带有标记点,求在满足这个条件的情况下,所需要标记点的最少个数. 1.POJ 3617 Best Cow Line http://poj.…

 Saruman's Army Time Limit:1000MS     Memory Limit:65536KB     64bit IO Format:%I64d & %I64u Submit Status Practice POJ 3069 Appoint description:  System Crawler  (2015-04-27) Description Saruman the White must lead his army along a straight path fro…

Saruman's Army Time Limit: 1000MS   Memory Limit: 65536K Total Submissions: 18794   Accepted: 9222 Description Saruman the White must lead his army along a straight path from Isengard to Helm’s Deep. To keep track of his forces, Saruman distributes s…

在一条直线上,有n个点.从这n个点中选择若干个,给他们加上标记.对于每一个点,其距离为R以内的区域里必须有一个被标记的点.问至少要有多少点被加上标记 Saruman the White must lead his army along a straight path from Isengard to Helm's Deep. To keep track of his forces, Saruman distributes seeing stones, known as palantirs, am…

地址 http://poj.org/problem?id=3069 题解 题目可以考虑贪心 尽可能的根据题意选择靠右边的点 注意 开始无标记点 寻找左侧第一个没覆盖的点 再来推算既可能靠右的标记点为一轮 我最开始就是轮次的操作理解错误 结果wa了 ac代码如下 #include <iostream> #include <vector> #include <algorithm> using namespace std; /* poj3069 题目大意:一个直线上有N个点.…

Saruman the White must lead his army along a straight path from Isengard to Helm’s Deep. To keep track of his forces, Saruman distributes seeing stones, known as palantirs, among the troops. Each palantir has a maximum effective range of R units, and…

Saruman's Army Time Limit : 2000/1000ms (Java/Other)   Memory Limit : 131072/65536K (Java/Other) Total Submission(s) : 3   Accepted Submission(s) : 2 Problem Description Saruman the White must lead his army along a straight path from Isengard to Helm…

Saruman the White must lead his army along a straight path from Isengard to Helm's Deep. To keep track of his forces, Saruman distributes seeing stones, known as palantirs, among the troops. Each palantir has a maximum effective range of R units, and…

Saruman's Army Time Limit: 1000MS   Memory Limit: 65536K Total Submissions: 8477   Accepted: 4317 Description Saruman the White must lead his army along a straight path from Isengard to Helm’s Deep. To keep track of his forces, Saruman distributes se…

http://poj.org/problem?id=3069 Saruman the White must lead his army along a straight path from Isengard to Helm’s Deep. To keep track of his forces, Saruman distributes seeing stones, known as palantirs, among the troops. Each palantir has a maximum…

POJ 3069 Saruman's Army(萨鲁曼军) Time Limit: 1000MS   Memory Limit: 65536K [Description] [题目描述] Saruman the White must lead his army along a straight path from Isengard to Helm’s Deep. To keep track of his forces, Saruman distributes seeing stones, know…

Description Saruman the White must lead his army along a straight path from Isengard to Helm’s Deep. To keep track of his forces, Saruman distributes seeing stones, known as palantirs, among the troops. Each palantir has a maximum effective range of …

Saruman's Army Time Limit: 1000MS   Memory Limit: 65536K Total Submissions: 13242   Accepted: 6636 Description Saruman the White must lead his army along a straight path from Isengard to Helm's Deep. To keep track of his forces, Saruman distributes s…

题目连接 Description Saruman the White must lead his army along a straight path from Isengard to Helm's Deep. To keep track of his forces, Saruman distributes seeing stones, known as palantirs, among the troops. Each palantir has a maximum effective rang…

Saruman the White must lead his army along a straight path from Isengard to Helm's Deep. To keep track of his forces, Saruman distributes seeing stones, known as palantirs, among the troops. Each palantir has a maximum effective range of R units, and…

简单贪心. 从左边开始,找 r 以内最大距离的点,再在该点的右侧找到该点能覆盖的点.如图. 自己的逻辑有些混乱,最后还是参考书上代码.(<挑战程序设计> P46) /****************************************** Problem: 3069 User: Memory: 668K Time: 16MS Language: G++ Result: Accepted ******************************************/ #inc…

一.题面 POJ3069 二.题意分析 我的理解是,可以在每个点设置一个监测点,能够监测到范围R内的所有其他点,那么问给出N个点的一维位置,需要在其中挑多少个监测点把所有点都监测到. 贪心解决: 1.先排序. 2.考虑第一个点,因为每个点是必须要监测的,那么第一个点需要被监测到,它可以是监测点,也可以是被监测点.贪心的想,为了能监测更多的点,让第一个点作为被监测的点,且是监测范围内最边界上的点. 3.现在需要考虑,当第一个点往右探测R范围时,最后一个点将是需要设置的监测点. 4.以这个监测点再往…

万恶之源 目录 题意 思路 贪心的原则是什么呢? 错解 正解 代码实现 书上的代码 我的代码 比较一下 问题 题意 给定若干个点的坐标,与范围R.每个点可以选择是否标记,标记后这个点的左右范围R内的所有点也会被标记,求为使所有点被标记,我们要主动标记多少个点. 思路 这题总感觉可以用搜索做,毕竟每个点的状态要么是1要么是0.但这是书上贪心的例题,那肯定得用贪心做啦. 贪心的原则是什么呢? 错解 首先我们的目标是尽可能少的标记,因此我们当然可以希望每次一次性标记的点越多越好,那么我们是不是可以遍历…

https://vjudge.net/problem/POJ-3069 弄清楚一点,第一个stone的位置,考虑左右两边都要覆盖R,所以一般情况下不会在左边第一个(除非前两个相距>R). 一开始二层循环外层写的i=1,这样对于数据诸如1 1 1=>0,而其实结果是1. #include<iostream> #include<cstdio> #include<queue> #include<cstring> #include<algorith…

题目描述 Best Cow Line (POJ 3617) 给定长度为N的字符串S,要构造一个长度为N字符串T.T是一个空串,反复执行下列任意操作: 从S的头部删除一个字符,加到T的尾部: 从S的尾部删除一个字符,加到T的尾部: 目标是要构造字典序尽可能小的字符串T. 限制条件 1 <= N <= 2000 字符串 S 只包含大写英文字母 样例输入 N = 6 S = "ACDBCB" 样例输出 ABCBCD (如下图所示进行操作) 思路分析 不断取S的开头和结尾中较小的一…

链接:http://poj.org/problem?id=3069 题解 #include<iostream> #include<algorithm> using namespace std; ; int N,R; // N是部队数,R是有效射程 int X[MAX]; void solve(){ sort(X,X+N); ,ans=; while(i<N){ // s是没有被覆盖的最左边的点的位置 int s=X[i++]; //一直向右前进直到距 s的距离大于 R的点,此…

此题的策略是选取可用范围最右边的点,一般来说该点辐射两边,左侧辐射,右侧辐射,所以用两个循环,第一个循环找出该点,第二个循环求出最右边的点 源代码: #include<iostream>#include<algorithm>using namespace std;#define maxn 1100int main(){    int r,n,k=0,num=0,x,a[maxn];    cin>>n;    for(int i=0;i<n;i++) cin>…

2015-09-06 萨鲁曼军队 问题大意:萨鲁曼白想要让他的军队从sengard到Helm’s Deep,为了跟踪他的军队,他在军队中放置了魔法石(军队是一条线),魔法石可以看到前后距离为R的距离,为了让魔法石发挥最大的效益,魔法石戴在军人的身上,问你怎么才能使用最少的石头 问题很清晰,思路也很清晰,这道题挺典型的,就是贪心算法, 很容易想到的就是我们只用在距离内找到最后的点(人),然后把魔法石放到其上面就行了,然后依次类推,最后就可以达到最少的数量 具体可以以2R为一次循环,在前R的区间内我…

直线上有N个点.点i的位置是Xi.从这N个点中选择若干个,给它们加上标记.对每一个点,其距离为R以内的区域里必须又带有标记的点(自己本身带有标记的点,可以认为与其距离为0的地方有一个带有标记的点).在满足这个条件的情况下,希望能为尽可能少的点添加标记.请问至少要有多少点被加上标记? #include "iostream" #include "algorithm" using namespace std; const int MAX_N = 1000; int N=6…

直线上有N个点. 点i的位置是Xi.从这N个点中选择若干个,给它们加上标记. 对每一个点,其距离为R以内的区域里必须有带有标记的点(自己本身带有标记的点, 可以认为与其距离为 0 的地方有一个带有标记的点). 在满足这个条件的情况下, 希望能为尽可能少的点添加标记. 请问至少要有多少点被加上标记? 输入 N = 6 R = 10 X = (1, 7, 15, 20, 30, 50} 输出 3 java实现 import java.util.Scanner; public class Main {…

萨鲁曼的军队(Saruman's Army) 代码(C) 本文地址: http://blog.csdn.net/caroline_wendy 题目: 直线上有N个点, 每个点, 其距离为R以内的区域里, 必须带有标记的点, 本身的距离为0. 尽可能少的加入�标记点, 至少要有多少点被加上标记? 贪心算法, 从最左边的点開始, 依次查找距离为R须要加入�标记的点, 直到结束. 代码: /* * main.cpp * * Created on: 2014.7.17 * Author: spike *…

Saruman's Army Time Limit: 1000MS   Memory Limit: 65536K Total Submissions: 6688   Accepted: 3424 Description Saruman the White must lead his army along a straight path from Isengard to Helm's Deep. To keep track of his forces, Saruman distributes se…

POJ3617 Best Cow Line 题意 给定长度为N的字符串S,要构造一个长度为N的字符串T.起初,T是一个空串,随后反复进行下列任意操作: 从S的头部(或尾部)删除一个字符,加到T的尾部 目标是构造字典序尽可能小的字符串T. 思路 贪心算法,不断取S的开头和末尾中较小的一个字符放到T的末尾.但对于S的开头和末尾字符相同的情况下,需要比较下一个字符大小,这可以用如下算法实现: 按照字典序比较S和S翻转后的字符串S1,如果S较小,则从S的开头取,否则从末尾取. 代码 Source Cod…

[SinGuLaRiTy-1024] Copyright (c) SinGuLaRiTy 2017. All Rights Reserved. [POJ 2709] 颜料 (Painter) 题目描述 杂货店出售一种由N(3<=N<=12)种不同颜色的颜料,每种一瓶(50ML),组成的颜料套装.你现在需要使用这N种颜料:不但如此,你还需要一定数量的灰色颜料.杂货店从来不出售灰色颜料——也就是它不属于这N种之一.幸运的是,灰色颜料是比较好配置的,如果你取出三种不同颜色的颜料各x ml,混合起来就…

Saruman's Army Time Limit: 1000MS   Memory Limit: 65536K Total Submissions: 5989   Accepted: 3056 Description Saruman the White must lead his army along a straight path from Isengard to Helm's Deep. To keep track of his forces, Saruman distributes se…