DNA Sorting
时间： 1ms 内存：64M
描述：
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.
输入：
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.
输出：
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.
示例输入：
10 6
AACATGAAGG
TTTTGGCCAA
TTTGGCCAAA
GATCAGATTT
CCCGGGGGGA
ATCGATGCAT示例输出：
CCCGGGGGGA
AACATGAAGG
GATCAGATTT
ATCGATGCAT
TTTTGGCCAA
TTTGGCCAAA提示：
参考答案（内存最优[752]）：
#include<stdio.h>
#include<string.h>
int main()
{
int n,m,i,j,s[105]={0},q,max=0;
char a[200][200];
scanf("%d%d",&n,&m);
getchar();
for(i=0; i<m; i++)
gets(a[i]);
for(i=0; i<m; i++)
{
for(j=0; j<n; j++)
for(q=j+1; q<n; q++)
if(a[i][j]>a[i][q])
s[i]++;
if(max<s[i])
max=s[i];
}
for(i=0; i<=max; i++)
for(j=0; j<m; j++)
if(s[j]==i)
puts(a[j]);
return 0;
}参考答案（时间最优[0]）：
#include <stdio.h>
#include <algorithm>
#include <iostream>
#include<string.h>
#include<math.h>
using namespace std;
struct DNA
{
char c[55];
int data;
} d[105];
int nixu(char *c)
{
int k=0;
int n=strlen(c);
for(int i=0; i<n; i++)
{
for(int j=i+1; j<n; j++)
if(c[i]>c[j])k++;
}
return k;
}
void paixu(int m)
{
for(int i=0; i<m; i++)
for(int j=0; j<m-i-1; j++)
if(d[j+1].data<d[j].data)
{
DNA a=d[j+1];
d[j+1]=d[j];
d[j]=a;
}
}
int main()
{
int n,m;
cin>>n>>m;
getchar();
for(int i=0; i<m; i++)
{
scanf("%s",d[i].c);
d[i].data=nixu(d[i].c);
}
paixu(m);
for(int i=0; i<m; i++)
puts(d[i].c);
return 0;
}
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