zoukankan      html  css  js  c++  java
  • POJ-3069

    Saruman's Army
    Time Limit: 1000MS   Memory Limit: 65536K
    Total Submissions: 10994   Accepted: 5555

    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 R units, and must be carried by some troop in the army (i.e., palantirs are not allowed to “free float” in mid-air). Help Saruman take control of Middle Earth by determining the minimum number of palantirs needed for Saruman to ensure that each of his minions is within R units of some palantir.

    Input

    The input test file will contain multiple cases. Each test case begins with a single line containing an integer R, the maximum effective range of all palantirs (where 0 ≤ R ≤ 1000), and an integer n, the number of troops in Saruman’s army (where 1 ≤ n ≤ 1000). The next line contains n integers, indicating the positions x1, …, xn of each troop (where 0 ≤ xi ≤ 1000). The end-of-file is marked by a test case with R = n= −1.

    Output

    For each test case, print a single integer indicating the minimum number of palantirs needed.

    Sample Input

    0 3
    10 20 20
    10 7
    70 30 1 7 15 20 50
    -1 -1

    Sample Output

    2
    4

    Hint

    In the first test case, Saruman may place a palantir at positions 10 and 20. Here, note that a single palantir with range 0 can cover both of the troops at position 20.

    In the second test case, Saruman can place palantirs at position 7 (covering troops at 1, 7, and 15), position 20 (covering positions 20 and 30), position 50, and position 70. Here, note that palantirs must be distributed among troops and are not allowed to “free float.” Thus, Saruman cannot place a palantir at position 60 to cover the troops at positions 50 and 70.

    题意:
    给n个点,在每个点的r范围内必须要有一个标记。

    贪心,从最左边开始找r内最远的点。

    AC代码:

     1 //#include<bits/stdc++.h>
     2 #include<iostream>
     3 #include<algorithm>
     4 #include<cstring>
     5 using namespace std;
     6 
     7 int a[1010];
     8 
     9 int main(){
    10     ios::sync_with_stdio(false);
    11     int r,n;
    12     while(cin>>r>>n&&r>=0&&n>=0){
    13         memset(a,0,sizeof(a));
    14         for(int i=0;i<n;i++){
    15             cin>>a[i];
    16         }
    17         sort(a,a+n);
    18         int temp=0,ans=0;
    19         while(temp<n){
    20             int s=a[temp++];
    21             while(temp<n&&a[temp]<=s+r){
    22                 temp++;
    23             }
    24             int cnt=a[temp-1];
    25             while(temp<n&&a[temp]<=cnt+r){
    26                 temp++;
    27             }
    28             ans++;
    29         }
    30         cout<<ans<<endl;
    31     }
    32     return 0;
    33 }
  • 相关阅读:
    解决SharePoint 文档库itemadded eventhandler导致的上传完成后,编辑页面保持报错的问题,错误信息为“该文档已经被编辑过 the file has been modified by...”
    解决SharePoint 2013 designer workflow 在发布的报错“负载平衡没有设置”The workflow files were saved but cannot be run.
    随机实例,随机值
    Spring4笔记
    struts2笔记(3)
    struts2笔记(2)
    获取文本的编码类型(from logparse)
    FileUtil(from logparser)
    DateUtil(SimpleDateFormat)
    struts2笔记
  • 原文地址:https://www.cnblogs.com/Kiven5197/p/7265622.html
Copyright © 2011-2022 走看看