Sunscreen （贪心+优先队列）

To avoid unsightly burns while tanning, each of the C (1 ≤ C ≤ 2500) cows must cover her hide with sunscreen when they're at the beach. Cow i has a minimum and maximum SPF rating (1 ≤ minSPFi ≤ 1,000; minSPFi ≤ maxSPFi ≤ 1,000) that will work. If the SPF rating is too low, the cow suffers sunburn; if the SPF rating is too high, the cow doesn't tan at all........
The cows have a picnic basket with L (1 ≤ L ≤ 2500) bottles of sunscreen lotion, each bottle i with an SPF rating SPFi (1 ≤ SPFi ≤ 1,000). Lotion bottle i can cover coveri cows with lotion. A cow may lotion from only one bottle.
What is the maximum number of cows that can protect themselves while tanning given the available lotions?
Input
* Line 1: Two space-separated integers: C and L
* Lines 2..C+1: Line i describes cow i's lotion requires with two integers: minSPFi and maxSPFi 
* Lines C+2..C+L+1: Line i+C+1 describes a sunscreen lotion bottle i with space-separated integers: SPFi and coveri
Output
A single line with an integer that is the maximum number of cows that can be protected while tanning
Sample Input
3 2
3 10
2 5
1 5
6 2
4 1
Sample Output
2
题意：奶牛由两个防晒程度值minspf和maxspf，由L种spf不一样的防晒霜各有一定数量的瓶数。
要求防晒霜的spf的值大于奶牛的minspf且小于maxspf，问这些瓶数的防晒霜能最多能保护多少奶牛。
思路：贪心，优先队列
要想得最优数量，首先得进行排序
防晒霜比较好处理，按照spf值从小到大排序
奶牛排序时按照最大值maxspf从小到大排序，如果最大值maxspf相同则按照最小值minspf从小到大排序。
因为maxspf大的值对spf的选择的余地更多，所以先优先处理maxspf小的，整体上升序处理奶牛与防晒霜spf。

注意这里每头牛只能使用一种防晒霜。

#include
#include
#include
using namespace std;
struct node
{
    int x;
    int y;
}ci[2505],s[2505];
int cmp1(node a,node b)
{
    return a.y==b.y?a.x=ci[i].x&&s[j].x<=ci[i].y&&s[j].y>0)
            {
                cnt++;
                s[j].y--;
                break;//一头牛只能用一种
            }
        }
    }
    printf("%d\n",cnt);
    return 0;
}