Django-Model操作数据库(增删改查.连表结构) 一.数据库操作 1.创建model表        …

Inversions After Shuffle time limit per test 1 second memory limit per test 256 megabytes input standard input output standard output You are given a permutation of integers from 1 to n. Exactly once you apply the following operation to this permutat…

在Merge Sort的基础上改改就好了. public class Inversions { public static int inversions(int [] A,int p, int r) { if(p<r) { int q = (int) Math.floor( (p+r)/2 ); int left = inversions(A,p,q); int right = inversions(A,q+1,r); int c = combine(A,p,q,r); return left…

We have some permutation Aof [0, 1, ..., N - 1], where N is the length of A. The number of (global) inversions is the number of i < j with 0 <= i < j < N and A[i] > A[j]. The number of local inversions is the number of i with 0 <= i <…

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…

Swaps and Inversions Time Limit: 2000/1000 MS (Java/Others)    Memory Limit: 32768/32768 K (Java/Others)Total Submission(s): 2315    Accepted Submission(s): 882 Problem Description Long long ago, there was an integer sequence a.Tonyfang think this se…

Given a list of N integers A1, A2, A3,...AN, there's a famous problem to count the number of inversions in it. An inversion is defined as a pair of indices i < j such that Ai > Aj. Now we have a new challenging problem. You are supposed to count the…

Swaps and Inversions Time Limit: 2000/1000 MS (Java/Others)    Memory Limit: 32768/32768 K (Java/Others)Total Submission(s): 3588    Accepted Submission(s): 976 Problem Description Long long ago, there was an integer sequence a.Tonyfang think this se…

转自九野:http://blog.csdn.net/qq574857122/article/details/43643135 题目链接:点击打开链接 题意: 给定n ,k 下面n个数表示有一个n的排列, 每次操作等概率翻转一个区间,操作k次. 问: k次操作后逆序数对个数的期望. 思路: dp[i][j]表示 a[i] 在a[j] j前面的概率 初始就是 dp[i][j]  = 1( i < j ) 则对于翻转区间 [i, j], 出现的概率 P = 1 / ( n * (n+1) /2) 并且…

题目原文: An inversion in an array a[] is a pair of entries a[i] and a[j] such that i<j but a[i]>a[j]. Given an array, design a linearithmic algorithm to count the number of inversions. 分析: 如果没有性能限制,用插入排序算法可以实现.题目性能被限制在nlogn,又是归并排序的练习题,很显然要实现个归并排序,并在里面计…