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最新推荐文章于 2022-09-03 23:09:32 发布

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Saruman's Army

Time Limit: 1000MS		Memory Limit: 65536K
Total Submissions: 2668		Accepted: 1342

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 positionsx₁, …, x_n of each troop (where 0 ≤ x_i ≤ 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

下面是代码：
#include<iostream>
#include<algorithm>
using namespace std;
int a[1010];
int main()
{
    int R,N;
    while(cin>>R>>N)
    {
        if(R==-1&&N==-1)
            break;
        for(int i=0;i<N;i++)
            cin>>a[i];
        sort(a,a+N);
        int i=0,ans=0;
        while(i<N)
        {
            int s=a[i++];
            while(i<N&&a[i]<=s+R)
                i++;
            int p=a[i-1];
            while(i<N&&a[i]<=p+R)
                i++;
            ans++;
        }
        cout<<ans<<endl;
    }
    return 0;
}