基于比较的内排序算法（二）

昨天去面试小企鹅的时候，被让10分钟写排序，算法随意。当时有感排序算法还不够十分熟练，快排、堆排、归并这些根本往上写，怕哪里出问题。所以回来后，默着把七种内排序写了几次，巩固基础，以后争取10分钟三种简单，半小时写七种排序。

 

C/C++源码：Sort.cpp

#include <iostream>#include <cassert>#include <stack>#include <cstring>using namespace std;void bubble(int A[],int n);void select(int A[],int n);void insert(int A[],int n);void shell(int A[],int n);void quick(int A[],int n);void heap(int A[],int n);void merge(int A[],int n);typedef void (*FUNC)(int A[],int n);FUNC Sort_func[]={bubble,select,insert,shell,quick,heap,merge};const int Sort_num = sizeof(Sort_func)/sizeof(FUNC);string Sort_name[]={"bubble","select","insert","shell","quick","heap","merge"};const int N = 1024*1024*1024;const int NUMS_PER_LINE = 10;int main(int argc, char *argv[]){ string input("data.txt"), output("sort_output_"); if(argc==2){ input = argv[1]; }else if(argc==3){ input = argv[1]; output = argv[2]; } FILE *fptr=NULL; if((fptr=fopen(input.c_str(),"r"))!=NULL){ int *arr1=NULL, *arr2=NULL; arr1 = new int[N]; arr2 = new int[N]; if(arr1==NULL){ cout << "new arr1 failed" << endl; fclose(fptr); }else if(arr2==NULL){ cout << "new arr2 failed" << endl; fclose(fptr); }else{ int data, i=0; while(fscanf(fptr,"%d",&data)!=EOF){ arr1[i++]=data; } fclose(fptr); for(int c=Sort_num-1;c>=0;c--){ memmove(arr2,arr1,sizeof(int)*i); clock_t s,f; double timeUsed = 0.0; s = clock(); (*Sort_func[c])(arr2,i); f = clock(); timeUsed = (double)(f-s)/CLOCKS_PER_SEC; cout << Sort_name[c] << ":/t" << timeUsed << "s" << endl; assert(c>=0&&c<=9); if((fptr=fopen((output+(char)(c+'0')).c_str(),"w"))!=NULL){ for(int j=0;j<i;j++){ fprintf(fptr,"%d/t", arr2[j]); if(j%NUMS_PER_LINE==NUMS_PER_LINE-1) fprintf(fptr,"/n"); } fclose(fptr); }else{ cout << "Can't write outfile /"" << output << "/"" << endl; } } } }else{ cout << "Can't open input file /"" << input << "/"" << endl; } return 0;}void swap(int& a,int& b){ int tmp=a; a = b; b = tmp;}void bubble(int A[],int n){ for(int i=1;i<n;i++) for(int j=1;j<=n-i;j++) if(A[j]<A[j-1]) swap(A[j],A[j-1]);}void select(int A[],int n){ for(int i=0;i<n-1;i++){ int min = i; for(int j=i+1;j<n;j++){ if(A[j]<A[min]) min = j; } swap(A[i],A[min]); }}void insert(int A[],int n){ for(int i=1,j;i<n;i++){ int tmp = A[i]; for(j=0;j<i && A[j]<=tmp;j++) ; for(int k=i-1;k>=j;k--) A[k+1]=A[k]; A[j]=tmp; }}void shell(int A[],int n){ int h; for(h=1;h<n/9;h=3*h+1); for(;h>0;h/=3){ for(int i=h,j;i<n;i+=h){ int tmp = A[i]; for(j=0;j<i && A[j]<=tmp;j+=h); for(int k=i-h;k>=j;k-=h) A[k+h]=A[k]; A[j]=tmp; } }}struct node{ node(int a,int b):l(a),r(b){} int l,r;};void quick(int A[],int n){ stack<node*> s; s.push(new node(0,n-1)); while(!s.empty()){ int l=s.top()->l; int r=s.top()->r; s.pop(); if(l<r){ int i=l, j=r; int pivot = A[l]; while(i<j){ while(A[i]<=pivot && i<=j) i++; while(A[j]>=pivot && i<=j) j--; if(i<j) swap(A[i],A[j]); } swap(A[l],A[j]); if(j-1-l>0) s.push(new node(l,j-1)); if(r-j-1>0) s.push(new node(j+1,r)); } }}void heapify(int A[],int i, int n){#define LC(i) (2*i+1)#define RC(i) (2*i+2)#define PAR(i) ((i-1)/2) if(i<n/2){ int max = A[i], f = 0; if(max < A[LC(i)] && LC(i) < n) max = A[LC(i)], f = 1; if(max < A[RC(i)] && RC(i) < n) f = 2; if(1==f){ swap(A[i],A[LC(i)]); heapify(A,LC(i),n); }else if(2==f){ swap(A[i],A[RC(i)]); heapify(A,RC(i),n); } }}void heap(int A[],int n){ if(n<=1) return; for(int i=n/2-1;i>=0;i--) heapify(A,i,n); swap(A[0],A[n-1]); for(int i=n-2;i>=1;i--){ heapify(A,0,i+1); swap(A[0],A[i]); }}void merge1(int A[],int l, int r){ if(l<r){ int mid = (r-l)/2+l; merge1(A,l,mid); merge1(A,mid+1,r); int *bak = new int[r-l+1]; int i=0,j=l,k=mid+1; while(j<=mid && k<=r) bak[i++]=(A[j]<A[k]?A[j++]:A[k++]); while(j<=mid) bak[i++]=A[j++]; while(k<=r) bak[i++]=A[k++]; memmove(A+l,bak,sizeof(int)*i); }}void merge(int A[],int n){ merge1(A,0,n-1);}

 

 

C/C++源码：data.cpp

用来产生一定规模的随机数据，测试排序

#include <iostream>#include <cstring>#include <ctime>#include <cstdlib>using namespace std;long long cal(char s[]){ long long sum =0; int len = strlen(s); for(int i=0;i<len;i++){ sum += sum*9 + (s[i]-'0'); } return sum;}const int NAME_LEN = 128;const int N = 1024*1024;int main(int argc, char *argv[]){ srand(time(NULL)); long long scale = 10000; char filename[NAME_LEN] = "data.txt"; if(argc==2){ scale = cal(argv[1]); }else if(argc ==3){ scale = cal(argv[1]); strcpy(filename,argv[2]); } FILE *fptr = NULL; if((fptr=fopen(filename,"w"))!=NULL){ for(long long i=0;i<scale;i++){ fprintf(fptr, "%d/t", rand()%N); if(i%10==9) fprintf(fptr, "/n"); } }else{ cout << "Can't write file" << endl; } return 0;}

 

用data产生10W的随机数据，运行时间如下：

 

当运行已经有序的10W数据时，运行时间如下：

 

 运行100W随机数据集时，运行时间如下：

 

运行100随机数据集，并且每种算法运行1024*16次，运行时间如下：

 

运行10随机数据，并且每种算法运行1024*128次，运行时间如下：