1007:DNA Sorting
- 时间限制:
- 1000ms
- 内存限制:
- 65536kB
- 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.
- 样例输入
-
10 6 AACATGAAGG TTTTGGCCAA TTTGGCCAAA GATCAGATTT CCCGGGGGGA ATCGATGCAT
- 样例输出
-
CCCGGGGGGA AACATGAAGG GATCAGATTT ATCGATGCAT TTTTGGCCAA TTTGGCCAAA
题目的本质是计算逆序数,然后根据逆序数,对DNA序列进行排序
#include <stdio.h> #include <iostream> #include <string.h> using namespace std; int main() { /* recept the parameters */ int length = 0; int n = 0; cin>>length; cin>>n; char **DNASeq = new char* [n]; for(int i=0; i<n; ++i) { DNASeq[i] = new char[length]; cin>>DNASeq[i]; } /* calculate the number of inversions */ int *inversions = new int [n]; for(int i=0; i<n; ++i) { inversions[i] = 0; /* initiate the array of inversion number */ for(int j=0; j<length; ++j) for(int k=j+1; k<length; ++k) if( DNASeq[i][j]>DNASeq[i][k]) inversions[i]++; } /*Bubble sort*/ for(int i=0; i<n; ++i) for(int j=n-1; j>i; --j) if( inversions[j] < inversions[j-1]) { int temp = inversions[j]; /*swap*/ inversions[j] = inversions[j-1]; inversions[j-1] = temp; char *tmp = DNASeq[j]; DNASeq[j] = DNASeq[j-1]; DNASeq[j-1] = tmp; } /*OUTPUT*/ for(int i=0; i<n; ++i) { cout<<DNASeq[i]<<endl; } return 0; }
排序部分为简洁,使用的是冒泡排序,也可将 DNA序列 和 逆序值 做成一个数据结构,然后用STL的sort排序,应该可以更加简洁。