> #include<stdio.h>
> #include<string.h>
> #include<stdlib.h>
> typedef struct DNAxu
> {
>     char str[120];
>     int num; 
> }DNAxu;
> void Msort(DNAxu SR[],DNAxu TR1[],int s,int t);
> int main()
> {
>     DNAxu DNA[100];
>     int len,row;
>     int i,j;
>     int a[4]={0},count;
>     scanf("%d%d",&len,&row);                           
>     for(j=0;j<row;j++)
>        scanf("%s",DNA[j].str);
>     for(i=0;i<row;i++)
>     {  
>         memset(a,0,sizeof(a));
>         count=0; 
>         for(j=len-1;j>=0;j--)
>         {
>             switch( DNA[i].str[j] ){
>                         case 'A':
>                                 a[1]++; 
>                                 a[2]++; 
>                                 a[3]++; 
>                                 break;  
>                         case 'C':
>                                 a[2]++; 
>                                 a[3]++; 
>                                 count += a[1];
>                                 break;  
>                         case 'G':
>                                 a[3]++; 
>                                 count += a[2];
>                                 break;  
>                         case 'T':
>                                 count += a[3];
>                 } 
>         }
>         DNA[i].num=count;
>     }
>     Msort(DNA,DNA,0,row-1);
>     for(i=0;i<row;i++)
>        printf("%s\n",DNA[i].str);
>     system("pause");
>     return 0;
> }
> 
> void Merge(DNAxu SR[],DNAxu TR[],int i,int m,int n)
> {
> 	int j,k,a,b;
> 	for(j=m+1,k=i;i<=m && j<=n;++k)
> 	{
> 		if(SR[i].num <= SR[j].num)
> 			TR[k]=SR[i++];
> 		else  TR[k]=SR[j++];
> 	}
> 	if(i<=m)
>      {
>              for(a=k,b=i;a<=n&&b<=m;a++,b++)
>              TR[a]=SR[b];
>      }
>      if(j<=n)
>      {
>              for(a=k,b=j;a<=n&&b<=n;a++,b++)
>              TR[a]=SR[b];
>      }
> }
> 
> void Msort(DNAxu SR[],DNAxu TR1[],int s,int t)
> {
> 	int m;
> 	if(s==t)
> 		TR1[s]=SR[s];
> 	else
> 	{
>         DNAxu TR2[51];
> 		m=(s+t)/2;
> 		Msort(SR,TR2,s,m);
> 		Msort(SR,TR2,m+1,t);
> 		Merge(TR2,TR1,s,m,t);
> 	}
> }