北大poj- 1007

DNA排序
逆序数可以用来描述一个序列混乱程度的量。例如,“DAABEC”的逆序数为5,其中D大于他右边的4个数,E大于他右边的1个数,4+1=5;又如,“ZWQM”的逆序数为3+2+1+0=6。
现在有许多长度一样的字符串,每个字符串里面只会出现四种字母(A,T,G,C)。要求编写程序,将这些字符串按照他们的逆序数进行排序。
输入:
输入数据有多组,以EOF结束。其中,每组数据:
第一行包括两个正整数,第一个正整数N给出了字符串的长度,第二个正整数M给出了字符串的数量。(1<=N,M<=100)
输出:
输出每组数据,不需要额外空行。
将输入的字符串按照其逆序数进行排序,如果两个字符串的逆序数相等,则按照输入中两者先后顺序进行排序。

Sample Input

10 6
AACATGAAGG
TTTTGGCCAA
TTTGGCCAAA
GATCAGATTT
CCCGGGGGGA
ATCGATGCAT

Sample Output

CCCGGGGGGA
AACATGAAGG
GATCAGATTT
ATCGATGCAT
TTTTGGCCAA
TTTGGCCAAA

Source

分析:要求用稳定的排序算法,所以选择了归并排序。计算逆序数原本没想太多用的暴力遍历,但是后来看评论,发现大神的一种有趣的算法。

  1 #include <stdio.h>
  2 #include <stdlib.h>
  3 #include <string.h>
  4 
  5 #define DNA_LEN 50
  6 #define DNA_NUM 100
  7 
  8 #define BUFFER_SIZE 10000
  9 
 10 typedef struct
 11 {
 12     int unsortedness;
 13     char dnaString[DNA_LEN];
 14 }Dna;
 15 
 16 typedef struct
 17 {
 18     int dnaLen;
 19     int dnaNum;
 20     Dna dna[DNA_NUM];
 21     Dna* pDna[DNA_NUM];
 22 }DnaSequence;
 23 
 24 DnaSequence DnaSeq;
 25 
 26 void GetDnaSequence(DnaSequence *dnaSeq)
 27 {
 28     int i;
 29 
 30     scanf("%d %d\n", &dnaSeq->dnaLen, &dnaSeq->dnaNum);
 31 
 32     for(i = 0; i < dnaSeq->dnaNum; i++)
 33     {
 34         if(NULL == gets(dnaSeq->dna[i].dnaString)) break;
 35 
 36         dnaSeq->pDna[i] = &dnaSeq->dna[i];
 37     }
 38 }
 39 
 40 void PrintDnaSequence(DnaSequence *dnaSeq)
 41 {
 42     int i;
 43 
 44     for(i = 0; i < dnaSeq->dnaNum; i++)
 45     {
 46         printf("%s\n", dnaSeq->pDna[i]->dnaString);
 47     }
 48 }
 49 /*
 50 void CalcUnsortedness(Dna* dna, int dnaLen)
 51 {
 52     int delta,i,j;
 53     dna->unsortedness = 0;
 54     for(i = 0; i < dnaLen; i++)
 55     {
 56         for(j = i+1; j < dnaLen; j++)
 57         {
 58             delta = dna->dnaString[i] - dna->dnaString[j];
 59             if(delta > 0) dna->unsortedness++;
 60         }
 61     }
 62 }
 63 */
 64 void CalcUnsortedness(Dna* dna, int dnaLen)
 65 {
 66     int i;
 67     int A = 0, C = 0, G = 0;
 68     dna->unsortedness = 0;
 69     for(i = dnaLen - 1; i >= 0; i--)
 70     {
 71         switch(dna->dnaString[i])
 72         {
 73             case 'A':
 74                 A++;
 75                 break;
 76             case 'C':
 77                 C++;
 78                 dna->unsortedness += A;
 79                 break;
 80             case 'G':
 81                 G++;
 82                 dna->unsortedness += A+C;
 83                 break;
 84             case 'T':
 85                 dna->unsortedness += A+C+G;
 86                 break;
 87             default:
 88                 break;
 89         }
 90     }
 91 }
 92 
 93 int SortCmp(const void* elem1, const void* elem2)
 94 {
 95     Dna* dna1 = (Dna *)(*(size_t*)elem1);
 96     Dna* dna2 = (Dna *)(*(size_t*)elem2);
 97 
 98     return dna1->unsortedness - dna2->unsortedness;
 99 }
100 
101 char g_mergeBuffer[BUFFER_SIZE];
102 
103 void Merge(char* array, int elemSize, int left, int mid, int right, int (*SortCmp)(const void*, const void*))
104 {
105     int i = left;
106     int j = mid;
107     int bufIdx = 0;
108 
109     while(i < mid && j <= right)
110     {
111         if(SortCmp(&array[i*elemSize], &array[j*elemSize]) <= 0)
112         {
113             memcpy(&g_mergeBuffer[bufIdx], &array[i*elemSize], elemSize);
114             i++;
115         }
116         else
117         {
118             memcpy(&g_mergeBuffer[bufIdx], &array[j*elemSize], elemSize);
119             j++;
120         }
121         bufIdx += elemSize;
122     }
123 
124     for(; i < mid; i++)
125     {
126         memcpy(&g_mergeBuffer[bufIdx], &array[i*elemSize], elemSize);
127         bufIdx += elemSize;
128     }
129 
130     for(; j <= right; j++)
131     {
132         memcpy(&g_mergeBuffer[bufIdx], &array[j*elemSize], elemSize);
133         bufIdx += elemSize;
134     }
135 
136     memcpy(&array[left*elemSize], g_mergeBuffer, (right-left+1)*elemSize);
137 }
138 
139 void MergeSort(void* array, int arrayLen, int elemSize, int (*SortCmp)(const void*, const void*))
140 {
141     int loop, left, mid, right = 0;
142 
143     for(loop = 1; loop < arrayLen; loop *= 2)
144     {
145         left = 0;
146         right = 0;
147         while(right < arrayLen - 1)
148         {
149             mid = left + loop;
150             right = (mid + loop - 1 > arrayLen - 1) ? (arrayLen - 1) : (mid + loop - 1);
151             Merge((char*)array, elemSize, left, mid, right, SortCmp);
152             left = left + loop * 2;
153         }
154     }
155 }
156 
157 void ProcDnaSequence(DnaSequence *dnaSeq)
158 {
159     int i;
160     int elemSize = sizeof(dnaSeq->pDna[0]);
161 
162     for(i = 0; i < dnaSeq->dnaNum; i++)
163     {
164         CalcUnsortedness(&dnaSeq->dna[i], dnaSeq->dnaLen);
165     }
166     MergeSort(dnaSeq->pDna, dnaSeq->dnaNum, elemSize, SortCmp);
167 }
168 
169 int main()
170 {
171     GetDnaSequence(&DnaSeq);
172     ProcDnaSequence(&DnaSeq);
173     PrintDnaSequence(&DnaSeq);
174     return 0;
175 }

 

    原文作者:Online Judge POJ
    原文地址: https://www.cnblogs.com/bixiongquan/p/8488265.html
    本文转自网络文章,转载此文章仅为分享知识,如有侵权,请联系博主进行删除。
点赞

发表评论

电子邮件地址不会被公开。 必填项已用*标注