POJ 3069

#include <iostream>
#include <cstdio>
#include <cstdlib>
#include <algorithm>
#include <string>
#include <cstring> 
#include <vector>
#include <set>
#include <queue>
#include <map>
using namespace std;
const int MAXN = 1000 + 10;
const int MAXM = 1000000000 + 1000;
typedef long long LL;

/*
POJ 3069
【难题】
关键：从没标记的点开始，找到距离R内最远的那个点进行标记并以此类推
*/

int main(){
	int N,R;
	scanf("%d %d",&R,&N);		// N:number of roads, 	M:coins for guard
	while( !(N==-1 && R==-1) ){
		int v[MAXN] = {0};
		int x;
		for(int i=0; i<N; i++){
			scanf("%d",&(v[i]));
		}
		sort(v,v+N);
		int need = 0,i = 0,cnt = 0;
		while( i<N ){
			int range = v[i]+R;			//查找要标记的点的查找范围 
			while( v[i+1]<=range && i<N ){
				i++;
			}
			// 标记v[i]
			range = v[i]+R;
			while( v[i+1]<=range && i<N ){
				i++;
			}
			i++; 
			cnt++;						//一次标记完成 
		}
		cout << cnt << endl;
		scanf("%d %d",&R,&N);
	}
	return 0;
}