CF257A.Sockets
普及/提高-
通过率:0%
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题目描述
Vasya has got many devices that work on electricity. He's got n supply-line filters to plug the devices, the i -th supply-line filter has ai sockets.
Overall Vasya has got m devices and k electrical sockets in his flat, he can plug the devices or supply-line filters directly. Of course, he can plug the supply-line filter to any other supply-line filter. The device (or the supply-line filter) is considered plugged to electricity if it is either plugged to one of k electrical sockets, or if it is plugged to some supply-line filter that is in turn plugged to electricity.
What minimum number of supply-line filters from the given set will Vasya need to plug all the devices he has to electricity? Note that all devices and supply-line filters take one socket for plugging and that he can use one socket to plug either one device or one supply-line filter.
输入格式
The first line contains three integers n , m , k ( 1<=n,m,k<=50 ) — the number of supply-line filters, the number of devices and the number of sockets that he can plug to directly, correspondingly. The second line contains n space-separated integers a1,a2,...,an ( 1<=ai<=50 ) — number ai stands for the number of sockets on the i -th supply-line filter.
输出格式
Print a single number — the minimum number of supply-line filters that is needed to plug all the devices to electricity. If it is impossible to plug all the devices even using all the supply-line filters, print -1.
输入输出样例
输入#1
3 5 3 3 1 2
输出#1
1
输入#2
4 7 2 3 3 2 4
输出#2
2
输入#3
5 5 1 1 3 1 2 1
输出#3
-1
说明/提示
In the first test case he can plug the first supply-line filter directly to electricity. After he plug it, he get 5 (3 on the supply-line filter and 2 remaining sockets for direct plugging) available sockets to plug. Thus, one filter is enough to plug 5 devices.
One of the optimal ways in the second test sample is to plug the second supply-line filter directly and plug the fourth supply-line filter to one of the sockets in the second supply-line filter. Thus, he gets exactly 7 sockets, available to plug: one to plug to the electricity directly, 2 on the second supply-line filter, 4 on the fourth supply-line filter. There's no way he can plug 7 devices if he use one supply-line filter.