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.

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, …, x_n of each troop (where 0 ≤ x_i ≤ 1000). The end-of-file is marked by a test case with R = n = −1.

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

#define _CRT_SECURE_NO_DEPRECATE#include<iostream>#include<stdio.h>#include<stdlib.h>#include<string.h>#include<algorithm>#define MAX 1001using namespace std;int troop[MAX];void solve(){    int r, n, res;    while (cin >> r >> n){        if (r == -1 && n == -1)return;        res = 0;        for (int i = 0; i < n; i++)cin >> troop[i];        sort(troop, troop + n);        for (int i = 0, far; i < n;){            far = troop[i];            while (i < n&&troop[i] - far <= r)i++;            res++; //cout << "round:" << res << endl;            far = troop[i - 1];            while (i < n&&troop[i] - far <= r)i++;        }        cout << res << endl;    }}int main(){    solve();    //system("pause");    return 0;}