Description
One measure of ``unsortedness'' in a sequence is the number of pairs of entries that are out of order with respect to each other. For instance, in the letter sequence ``DAABEC'', this measure is 5, since D is greater than four letters to its right and E is greater than one letter to its right. This measure is called the number of inversions in the sequence. The sequence ``AACEDGG'' has only one inversion (E and D)---it is nearly sorted---while the sequence ``ZWQM'' has 6 inversions (it is as unsorted as can be---exactly the reverse of sorted).
You are responsible for cataloguing a sequence of DNA strings (sequences containing only the four letters A, C, G, and T). However, you want to catalog them, not in alphabetical order, but rather in order of ``sortedness'', from ``most sorted'' to ``least sorted''. All the strings are of the same length.
Input
The first line contains two integers: a positive integer n (0 < n <= 50) giving the length of the strings; and a positive integer m (0 < m <= 100) giving the number of strings. These are followed by m lines, each containing a string of length n.
Output
Output the list of input strings, arranged from ``most sorted'' to ``least sorted''. Since two strings can be equally sorted, then output them according to the orginal order.
Sample Input
10 6 AACATGAAGG TTTTGGCCAA TTTGGCCAAA GATCAGATTT CCCGGGGGGA ATCGATGCAT
Sample Output
CCCGGGGGGA AACATGAAGG GATCAGATTT ATCGATGCAT TTTTGGCCAA TTTGGCCAAA
思路:1、将数据存入multimap<string,int> 的键值对中。
2、利用冒泡排序的思想,来求逆序的数量。
3、根据逆序的数量,对multimap<string,int> 的键值对进行修改。
4、将multimap<string,int>的数据,存入multimap<int,string>中,这样可以偷个懒,不需要自己实现排序输出。
【注:】这个算法不是最优的,我是为了自己复习STL的相关操作。爱你哟,笔芯,欢迎交流。
#include <iostream>
#include <string>
#include <map>
#include <algorithm>
using namespace std;
int countFunction(string data)//利用冒泡排序的思路来计算逆序数
{
int Count=0;
for(int i=0;i<data.length();i++)
{
for(int j=i+1;j<data.length();j++){
if(data[i]>data[j])
Count++;
}
}
return Count;
}
int main()
{
/*
* 输入相关数据
*/
int m,n;
cin>>m>>n;
multimap<string,int> data;
multimap<int,string>result;
while (n--) {
string temp;
cin>>temp;
data.insert(pair<string,int>(temp,0));
}
/*
* 更新将每个字符串对应的逆序数
*/
multimap<string,int>::iterator iter;
for(iter=data.begin();iter!=data.end();iter++)
{
iter->second=countFunction(iter->first);
}
/*
* multimap<string,int> 转存到multimap<int,string>;利用关联容器会对键所在键值对进行排序。
*/
for(iter=data.begin();iter!=data.end();iter++)
{
result.insert(pair<int,string>(iter->second,iter->first));
}
/*
* 直接输出
*/
multimap<int,string>::iterator iter2;
for(iter2=result.begin();iter2!=result.end();iter2++)
{
cout<<iter2->second<<endl;
}
return 0;
}