A9528. Devu, the Singer and Churu, the Joker
编程题
普及/提高-
知识点
题目描述
Devu is a renowned classical singer. He is invited to many big functions/festivals. Recently he was invited to "All World Classical Singing Festival". Other than Devu, comedian Churu was also invited.
Devu has provided organizers a list of the songs and required time for singing them. He will sing $n$ songs, $i^{th}$ song will take $t_{i}$ minutes exactly.
The Comedian, Churu will crack jokes. All his jokes are of 5 minutes exactly.
People have mainly come to listen Devu. But you know that he needs rest of 10 minutes after each song. On the other hand, Churu being a very active person, doesn't need any rest.
You as one of the organizers should make an optimal sсhedule for the event. For some reasons you must follow the conditions:
- The duration of the event must be no more than $d$ minutes;
- Devu must complete all his songs;
- With satisfying the two previous conditions the number of jokes cracked by Churu should be as many as possible.
If it is not possible to find a way to conduct all the songs of the Devu, output -1. Otherwise find out maximum number of jokes that Churu can crack in the grand event.
Devu has provided organizers a list of the songs and required time for singing them. He will sing $n$ songs, $i^{th}$ song will take $t_{i}$ minutes exactly.
The Comedian, Churu will crack jokes. All his jokes are of 5 minutes exactly.
People have mainly come to listen Devu. But you know that he needs rest of 10 minutes after each song. On the other hand, Churu being a very active person, doesn't need any rest.
You as one of the organizers should make an optimal sсhedule for the event. For some reasons you must follow the conditions:
- The duration of the event must be no more than $d$ minutes;
- Devu must complete all his songs;
- With satisfying the two previous conditions the number of jokes cracked by Churu should be as many as possible.
If it is not possible to find a way to conduct all the songs of the Devu, output -1. Otherwise find out maximum number of jokes that Churu can crack in the grand event.
输入格式
The first line contains two space separated integers $n$ , $d$ $(1<=n<=100; 1<=d<=10000)$ . The second line contains $n$ space-separated integers: $t_{1},t_{2},...,t_{n}$ $(1<=t_{i}<=100)$ .
输出格式
If there is no way to conduct all the songs of Devu, output -1. Otherwise output the maximum number of jokes that Churu can crack in the grand event.
输入输出样例
输入 #1
3 30 2 2 1
输出 #1
5
输入 #2
3 20 2 1 1
输出 #2
-1
说明/提示
Consider the first example. The duration of the event is $30$ minutes. There could be maximum $5$ jokes in the following way:
- First Churu cracks a joke in $5$ minutes.
- Then Devu performs the first song for $2$ minutes.
- Then Churu cracks $2$ jokes in $10$ minutes.
- Now Devu performs second song for $2$ minutes.
- Then Churu cracks $2$ jokes in $10$ minutes.
- Now finally Devu will perform his last song in $1$ minutes.
Total time spent is $5+2+10+2+10+1=30$ minutes.
Consider the second example. There is no way of organizing Devu's all songs. Hence the answer is -1.
- First Churu cracks a joke in $5$ minutes.
- Then Devu performs the first song for $2$ minutes.
- Then Churu cracks $2$ jokes in $10$ minutes.
- Now Devu performs second song for $2$ minutes.
- Then Churu cracks $2$ jokes in $10$ minutes.
- Now finally Devu will perform his last song in $1$ minutes.
Total time spent is $5+2+10+2+10+1=30$ minutes.
Consider the second example. There is no way of organizing Devu's all songs. Hence the answer is -1.