摘要：
1 #include<iostream> 2 #include<cstdio> 3 #include<cstring> 4 #include<algorithm> 5 using namespace std; 6 int c[50005],tr,tl,f[30][50005],a[50005],s, 阅读全文
摘要：
题目描述 You are given an array of nn integers a_{1}...\ a_{n}a1... an . The cost of a subsegment is the number of unordered pairs of distinct indices w 阅读全文