Description 给定一个长度为 n(n≤5*10^5) 的序列 a,如果只允许进行比较和交换相邻两个数的操作求至少需要多少次交换才能把 a 从小到大排序. Input The input contains several test cases. Every test case begins with a line that contains a single integer n < 500,000 -- the length of the input sequence. Each of…
Description In this problem, you have to analyze a particular sorting algorithm. The algorithm processes a sequence of n distinct integers by swapping two adjacent sequence elements until the sequence is sorted in ascending order. For the input seque…
Description In this problem, you have to analyze a particular sorting algorithm. The algorithm processes a sequence of n distinct integers by swapping two adjacent sequence elements until the sequence is sorted in ascending order. For the input seque…
题目:http://poj.org/problem?id=2299 逆序对,注意树状数组维护后缀和. 代码如下: #include<iostream> #include<cstdio> #include<algorithm> #include<cstring> #define MAXN 500005 using namespace std; int n,f[MAXN]; long long da[MAXN],a[MAXN],ans; int query(in…