题目链接 Sequence II Time Limit: 5000/2500 MS (Java/Others)    Memory Limit: 32768/32768 K (Java/Others)Total Submission(s): 331    Accepted Submission(s): 151 Problem Description Long long ago, there is a sequence A with length n. All numbers in this se…

Sequence II Time Limit: 5000/2500 MS (Java/Others)    Memory Limit: 32768/32768 K (Java/Others) Problem Description Long long ago, there is a sequence A with length n. All numbers in this sequence is no smaller than 1 and no bigger than n, and all nu…

链接:http://poj.org/problem?id=2299 题意:给出n个数,求将这n个数从小到大排序,求使用快排的需要交换的次数. 分析:由快排的性质很容易发现,只需要求每个数的逆序数累加起来就行了.逆序数可以用树状数组求. n<500000,0<=a[i]<=999,999,999,很明显数组不可能开这么大,所以需要离散化. 可以用一个结构体 struct node{    int val,pos;}a[N]; pos表示每个数的下标,val表示该数的值 按val从小到大排序…

题目: 思路:先离散化数据然后树状数组搞一下求逆序数. 离散化的方法:https://blog.csdn.net/gokou_ruri/article/details/7723378 自己对用树状数组求逆序数的理解:输入数据并利用树状数组求出前边比它小和等于它的数据有几个,用输入数据的总的个数减去比它小的数就是比它大的数res,将所有的res加起来就是要求的序列的逆序数. 如图: 把所有的res加起来就是答案了 代码: #include <iostream> #include <cstd…

题目链接:http://acm.hdu.edu.cn/showproblem.php?pid=1394 Minimum Inversion Number                        Time Limit: 2000/1000 MS (Java/Others)    Memory Limit: 65536/32768 K (Java/Others)                                            Total Submission(s): 10…

传送门 E.sequence •题意 定义序列 p 中的 "good",只要 i 之前存在 pj < pi,那么,pi就是 "good": 求删除一个数,使得序列中 "good" 的个数最多: •题解 一个数 pi 对 "good" 的贡献有两个来源: ①pi 本身为"good",对答案的贡献为 1: ②删除 pi 后,i 之后的本来是 "good" 的数因为 pi 被删除而变成非…

题目链接:http://poj.org/problem?id=2299 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…

题意: 给你1-n的序列,然后有k次机会的操作,每一次你可以选择两个数交换. 求一个最大的逆序数. 思路: 感觉就是最后一个和第一个交换,然后往中间逼近,到最终的序列,用树状数组求一下逆序数. #include <iostream> #include <stdio.h> #include <string.h> #include <algorithm> using namespace std; #define MAX 100010 typedef __int6…

Minimum Inversion Number Time Limit: 2000/1000 MS (Java/Others)    Memory Limit: 65536/32768 K (Java/Others) Total Submission(s): 17737    Accepted Submission(s): 10763 Problem Description The inversion number of a given number sequence a1, a2, ...,…

题目连接:http://acm.hdu.edu.cn/showproblem.php?pid=6318 Problem Description Long long ago, there was an integer sequence a.Tonyfang think this sequence is messy, so he will count the number of inversions in this sequence. Because he is angry, you will ha…