A - DNA Sorting

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

10 6
AACATGAAGG
TTTTGGCCAA
TTTGGCCAAA
GATCAGATTT
CCCGGGGGGA
ATCGATGCAT

Sample Output

CCCGGGGGGA
AACATGAAGG
GATCAGATTT
ATCGATGCAT
TTTTGGCCAA
TTTGGCCAAA

這道題本來暴力迴圈排序就可以了，結果智障的小菜雞陣列開小了，一直Runtime Error 
誤以為迴圈超時，又去部落格看了看大牛的解法，再次拾起了結構體，
順帶了解了一波c++的sort和stable_sort;前前後後改了兩個小時
最後發現是陣列開小了，真是被自己蠢笑了

 

#include <iostream>
#include <cstdio>
#include <cstring>
#include <algorithm>
#include <string>
#include<stdlib.h>
using namespace std;
struct DNA
{
	string dna;
	int len;
};
bool compare(DNA x,DNA y)
{
	return x.len<y.len;
}
int main()
{
	struct DNA a[102];
	int i,j,n,m;
	scanf("%d%d",&n,&m);
	for(i=0;i<m;i++)
	{
		cin>>a[i].dna;
		a[i].len=0;
		for(j=0;j<=n-2;j++)
		{
			for(int k=j+1;k<=n-1;k++)
			{
				if(a[i].dna[j]>a[i].dna[k])
				{
					a[i].len++;
				}
			}
		}
	}
	stable_sort(a,a+m,compare);
	for(i=0;i<m;i++)
	{
		cout<<a[i].dna<<endl;
	}
	return 0;
}