CF1066B Heaters

思路：

从左向右贪心选择能覆盖当前位置的最靠右的那个heater即可，和poj radar installation类似。

实现：

 #include <iostream>
 #include <cassert>
 using namespace std;

 const int INF = 0x3f3f3f3f;

 int a[], cov[];

 int main()
 {
     int n, r;
     while (cin >> n >> r)
     {
         fill(cov + , cov + n + , -);
         for (int i = ; i <= n; i++) cin >> a[i];
         for (int i = ; i <= n; i++)
         {
             for (int j = max(, i - r + ); j <= min(n, i + r - ); j++)
             {
                 if (a[j] == ) cov[i] = j;
             }
         }
         int maxn = -INF, cnt = ;
         bool flg = true;
         for (int i = ; i <= n; i++)
         {
             if (maxn >= i - r +  && maxn <= i + r - ) continue;
             else if (cov[i] == -) { flg = false; break; }
             else
             {
                 maxn = cov[i];
                 cnt++;
             }
         }
         cout << (flg ? cnt : -) << endl;
     }
     return ;
 }