Joy is now applying for postgraduate programs. But due to his low GPA, no school really wants to receive him. One day poor Joy meet Aladdin, Aladdin promises to help him delete some of his courses he attended to increase his GPA. But now he is confused again, can you write a program to help him point out the maximum GPA he can get by deleting courses.
It should be mentioned that the calculation formula of GPA is Σ(s[i]*c[i])/Σ(s[i])
, where the academic credit of the i-th course is s[i] and the score of the i-th course is c[i]. And because of the limitation of power of the magic lamp, he could at most delete k courses.