[挑战程序设计竞赛] POJ 3069 - Saruman's Army

#include <stdio.h>
#include <string.h>
#include <math.h>
#include <stdlib.h>
#include <algorithm>
#include <iostream>
#include <set>
#include <map>
#include <queue>
#include <stack>
#include <assert.h>
#include <time.h>
typedef long long LL;
const int INF = 500000001;
const double EPS = 1e-9;
const double PI = acos(-1.0);
using namespace std;
int main()
{
//freopen("test0.in", "r", stdin);
//freopen("test0.out", "w", stdout);
//srand(time(NULL));
int N, R, a[1001];
while(~scanf("%d", &R))
{
scanf("%d", &N);
if(N == -1 && R == -1) break;
for(int i = 0; i < N; i++)
{
scanf("%d", &a[i]);
}
sort(a, a+N);
int left, mid;
int sum = 0;
int i = 0;
while(i < N)
{
left = a[i++];
while(left + R >= a[i]) i++;
mid = a[i-1];
while(mid + R >= a[i]) i++;
++sum;
}
printf("%d\n", sum);
}
return 0;
}