Q11369: Shopaholic

https://uva.onlinejudge.org/index.php?option=onlinejudge&Itemid=99999999&page=show_problem&category=&problem=2354&mosmsg=Submission+received+with+ID+17702604

這題很簡單就使是把商品價格存入陣列然後作排序最後從尾開始遞減3相加