POJ1007-DNA Sorting-ACM
DNA Sorting
| Time Limit: 1000MS | Memory Limit: 10000K | |
| Total Submissions: 83442 | Accepted: 33584 |
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.
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
重点，归并排序求逆序数
#include <stdio.h>
#include <malloc.h>
#include <string.h>
#define MAXN 256
char a[MAXN];
char c[MAXN];
int cnt=0;
void MergeSort(int l, int r){
int mid, i, j, tmp;
if( r > l+1 ){
mid = (l+r)/2;
MergeSort(l, mid);
MergeSort(mid, r);
tmp = l;
for( i=l, j=mid; i < mid && j < r; ){
if( a[i] > a[j] ){
c[tmp++] = a[j++];
cnt += mid-i; //
}
else c[tmp++] = a[i++];
}
if( j < r ) for( ; j < r; ++j ) c[tmp++] = a[j];
else for( ; i < mid; ++i ) c[tmp++] = a[i];
for ( i=l; i < r; ++i ) a[i] = c[i];
}
}
int main(void){
int n,m;
scanf("%d%d",&n,&m);
char ** strs = (char **)malloc(m*sizeof(char*));
int * cnts = (int *)malloc(m*sizeof(int));
int i;
for(i = 0;i<m;i++){
strs[i] = (char *)malloc((n+1)*sizeof(char));
scanf("%s",strs[i]);
//printf("%s\n",strs[i]);
cnt = 0;
strcpy(a,strs[i]);
//printf("%s\n",a);
MergeSort(0,n);
//printf("%d\n",cnt);
cnts[i] = cnt;
}
for(i = 0;i<m-1;i++){
int j,p=i;
for(j = i+1;j<m;j++){
if(cnts[p]>cnts[j]){
p = j;
}
}
if(p!=i){
int tmp = cnts[p];
cnts[p] = cnts[i];
cnts[i] = tmp;
char * str = strs[p];
strs[p] = strs[i];
strs[i] = str;
}
}
for(i = 0;i<m;i++){
printf("%s\n",strs[i]);
free(strs[i]);
}
free(strs);
free(cnts);
return 0;
}