摘要： " 题目链接 " Problem Description Give you an array A[1..n]of length n. Let f(l,r,k) be the k th largest element of A[l..r]. Specially , f(l,r,k)=0 if r−l+ 阅读全文

摘要： " 题目链接 " Problem Description RXD is a good mathematician. One day he wants to calculate: ∑i=1nkμ2(i)×⌊nki−−−√⌋ output the answer module 109+7. 1≤n,k≤1 阅读全文

摘要： " 题目链接 " Problem Description RXD has a tree T, with the size of n. Each edge has a cost. Define f(S) as the the cost of the minimal Steiner Tree of th 阅读全文