归并排序

来源：互联网发布：更换淘宝店铺负责人编辑：程序博客网时间：2024/06/06 19:39
#include <stdio.h>#include <stdlib.h>#define MAX 255int R[MAX];void Merge(int low,int m,int high){/* 将两个有序的子文件R[low..m)和R[m+1..high]归并成一个有序的 */ /* 子文件R[low..high] */ int i=low,j=m+1,p=0; /* 置初始值 */ int *R1; /* R1是局部向量，若p定义为此类型指针速度更快 */ R1=(int *)malloc((high-low+1)*sizeof(int)); if(!R1) /* 申请空间失败 */ {  puts("Insufficient memory available!");  return; } while(i<=m&&j<=high) /* 两子文件非空时取其小者输出到R1[p]上 */  R1[p++]=(R[i]<=R[j])?R[i++]:R[j++]; while(i<=m) /* 若第1个子文件非空，则复制剩余记录到R1中 */  R1[p++]=R[i++]; while(j<=high) /* 若第2个子文件非空，则复制剩余记录到R1中 */  R1[p++]=R[j++]; for(p=0,i=low;i<=high;p++,i++)  R[i]=R1[p];/* 归并完成后将结果复制回R[low..high] */} /* end of Merge */void Merge_SortDC(int low,int high){/* 用分治法对R[low..high]进行二路归并排序 */ int mid; if(low<high) {/* 区间长度大于1 */  mid=(low+high)/2; /* 分解 */  Merge_SortDC(low,mid); /* 递归地对R[low..mid]排序 */  Merge_SortDC(mid+1,high); /* 递归地对R[mid+1..high]排序 */  Merge(low,mid,high); /* 组合，将两个有序区归并为一个有序区 */ }}/* end of Merge_SortDC */void main(){ int i,n; //clrscr(); puts("Please input total element number of the sequence:"); scanf("%d",&n); if(n<=0||n>MAX) {  printf("n must more than 0 and less than %d.\n",MAX);  exit(0); } puts("Please input the elements one by one:"); for(i=1;i<=n;i++)  scanf("%d",&R[i]); puts("The sequence you input is:"); for(i=1;i<=n;i++)  printf("%4d",R[i]); Merge_SortDC(1,n); puts("\nThe sequence after merge_sortDC is:"); for(i=1;i<=n;i++)  printf("%4d",R[i]); puts("\n Press any key to quit..."); getchar();}
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