简洁的排序算法实现

插入排序 Insert Sort

template <class Elem,class Comp>void inssort(Elem A[],int n){  for (int i = 1; i < n; i++)    for (int j = i; (j > 0)&&(Comp::lt(A[j],A[j-1])); j--)        swap(A,j,j-1);}

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冒泡排序 Bubble Sort

template <class Elem,class Comp>void bubsort(Elem A[],int n){  for (int i = 0; i < n-1; i++)    for (int j = n-1; j > i; j--)      if (Comp::lt(A[j],A[j-1]))        swap(A,j,j-1);}

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选择排序 Selection Sort

template <class Elem,class Comp>void selsort(Elem A[],int n){    for (int i = 0; i < n-1; ++i){        int lowindex = i;        for (int j = n-1; j > i ; j--)            if (Comp::lt(A[j],A[lowindex]))                lowindex = j;        swap(A,i,lowindex);              }}

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希尔排序 Shellsort

template <class Elem,class Comp>void inssort2(Elem A[],int n,int incr){  for (int i = incr ; i < n; i+=incr)    for (int j = i; (j >= incr)&&Comp::lt(A[j],A[j-incr]); j-=incr)      swap(A,j,j-incr);}template <class Elem,class Comp>void shellsort(Elem A[],int n){  for (int i = n/2; i >= 2; i/=2)    for (int j = 0; j < i; ++j)      inssort2<Elem,Comp>(&A[j],n,i);  inssort2<Elem,Comp>(A,n,1);}

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快速排序 Quicksort

//Here is a simple implement of findpivot,but it is better to pick a value at randomtemplate <class Elem>int findpivot(Elem A[],int i,int j){  return (i+j)/2;}template <class Elem,class Comp>void partition(Elem A[],int l,int r,Elem& pivot){  do{    while(Comp::lt(A[++l],pivot));    while((r!=0)&&Comp::gt(A[--r],pivot));    swap(A,l,r);  }while(l<r);  swap(A,l,r);//Reverse last,wasted swap  return l;}template <class Elem,class Comp>void quicksort(Elem A[],int i,int j){  if(j <= i) return;// Don't sort 0 or 1 Elem  int pivotindex = findpivot(A,i,j);  swap(A,pivotindex,j);  int k = partition(A,i-1,j,A[j]);  swap(A,k,j);  quicksort<Elem,Comp>(A,i,k-1);  quicksort<Elem,Comp>(A,k+1,j);}

以上为书中源码，下面为本人胆大妄为，略微改进后的代码

template <class Elem,class Comp>void partition(Elem A[],int l,int r,Elem pivot){  do{    while(l<r&&Comp::lt(A[l],pivot)) l++;    A[r] = A[l];    while(l<r&&Comp::gt(A[r],pivot) r--;    A[l] = A[r];  }while(l<r);  return l;}template <class Elem,class Comp>void quicksort(Elem A[],int i,int j){  if(j <= i) return;// Don't sort 0 or 1 Elem  int pivotindex = findpivot(A,i,j);  Elem pivot = A[pivotindex];//save pivot   swap(A,pivotindex,j);  int k = partition(A,i,j,pivot);  A[k] = pivot;  quicksort<Elem,Comp>(A,i,k-1);  quicksort<Elem,Comp>(A,k+1,j);}

减少了交换函数中的中间变量的开支

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归并排序 Mergesort

template <class Elem,class Comp>void mergesort(Elem A[],Elem temp[],int left,int right,int minsortlen){    if(left == right) return;    //use Insertion Sort to sort small subarrays    if((right-left) <= minsortlen){        inssort<Elem,Comp>(&A[left],right-left+1);        return;    }    int i,j,k,mid = (left+right)/2;    mergesort<Elem,Comp>(A,temp,left,mid,minsortlen);    mergesort<Elem,Comp>(A,temp,mid+1,right,minsortlen);    for (i = mid; i >= left; i--)        temp[i]=A[i];    for (j = 1; j <= right-mid; j++)        temp[right-j+1] = A[j+mid];    for (i = left,j = right,k = left;k<=right;k++)        if (temp[i] < temp[j])             A[k] = temp[i++];        else            A[k] = temp[j--];}

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基数排序 Radix Sort

template <class Elem,class Comp>//cnt[i] stores number of records in bin[i]void radix(Elem A[],Elem B[],int r,int n,int k,int cnt[]){    int j;    for (int i = 0,rtok = 1; i < k; ++i,rtok*=r){        for (j = 0;j < r;j++)            cnt[j] = 0;        //Count the number of records for each bin on this pass        for (j = 0;j < n;j++)            cnt[(A[j]/rtok)%r]++;        //cnt[j] will be index for last slot of bin j        for (j = 1;j < r;j++)            cnt[j] = cnt[j] + cnt[j-1];        for (j = n-1;j >= 0;j--)            B[--cnt[(A[j]/rtok)%r]] = A[j];        for (j = 0;j < n;j++)            A[j] = B[j];    }}

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Appendix Utility Functions

template <class Elem,class Comp>inline void swap(Elem A[],int i,int j){  Elem t = A[i];  A[i] = A[j];  A[j] = t;}

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参考书籍：数据结构与算法分析（c++版）（第二版）（作者：Clifford A.Shaffer）

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有错误的地方望指出，谢谢！

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持续更新

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欢迎转载，但请附上原地址http://blog.csdn.net/jiaxingzheng/article/details/48713911，谢谢！