Question

我正在尝试使用堆栈实现快速排序，这是代码

#include <iostream>
#include <cstdlib>
using namespace std;
template<class Item>
class STACK{
private:
    Item *a;int n;
public:
    STACK(int maxN){

        a=new Item[maxN];n=0;

    }
    int empty()const {
        return n==0;

    }
    void push(Item item){
        a[n++]=item;
        }
   Item pop() {
        return a[--n];

   }


};
template<class Item>
int partition (Item a[],int l,int r){

    int i=l-1;
    int j=r;
    Item v=a[r];
     for (;;){

          while (a[++i]<v);
          while (v<a[--j])  if (j==i) break;
           if (i>=j) break;
            Item t=a[i];
            a[i]=a[j];
            a[j]=t;
     }

      Item s=a[i];
       a[i]=a[r];
       a[r]=s;
       return i;
       }
inline void push2(STACK<int>&s,int a,int b){
    s.push(b);
    s.push(a);
    }

template<class Item>
  void quicksort(Item a[],int l,int r){

       STACK<int> s(50);
       push2(a,l,r);
       while (!s.empty()){
           int l=s.pop();
           int r=s.pop();
              if (r<=l) continue;
              int i=partition(a,l,r);
               if(i-1>r-1)
               { push2(a,l,i-1);  push2(a,i+1,r);
               }
               else{
                   push2(a,i+1,r);
                   push2(a,l,i-1);



               }

       }



  }

int main(){

    int a[]={45,12,30,67,11,17,50,78};
    int n=sizeof(a)/sizeof(a[0]);
    quicksort(a,0,n-1);
     for (int i=0;i<n;i++)
         cout<<a[i]<< "  ";




     return 0;

}

但这里有错误

------ Build started: Project: sort_stack, Configuration: Debug Win32 ------
1>  sort_stack.cpp
1>c:\users\david\documents\visual studio 2010\projects\sort_stack\sort_stack.cpp(65): error C2664: 'push2' : cannot convert parameter 1 from 'int []' to 'STACK<Item> &'
1>          with
1>          [
1>              Item=int
1>          ]
1>          c:\users\david\documents\visual studio 2010\projects\sort_stack\sort_stack.cpp(92) : see reference to function template instantiation 'void quicksort<int>(Item [],int,int)' being compiled
1>          with
1>          [
1>              Item=int
1>          ]
1>c:\users\david\documents\visual studio 2010\projects\sort_stack\sort_stack.cpp(72): error C2664: 'push2' : cannot convert parameter 1 from 'int []' to 'STACK<Item> &'
1>          with
1>          [
1>              Item=int
1>          ]
1>c:\users\david\documents\visual studio 2010\projects\sort_stack\sort_stack.cpp(72): error C2664: 'push2' : cannot convert parameter 1 from 'int []' to 'STACK<Item> &'
1>          with
1>          [
1>              Item=int
1>          ]
1>c:\users\david\documents\visual studio 2010\projects\sort_stack\sort_stack.cpp(75): error C2664: 'push2' : cannot convert parameter 1 from 'int []' to 'STACK<Item> &'
1>          with
1>          [
1>              Item=int
1>          ]
1>c:\users\david\documents\visual studio 2010\projects\sort_stack\sort_stack.cpp(76): error C2664: 'push2' : cannot convert parameter 1 from 'int []' to 'STACK<Item> &'
1>          with
1>          [
1>              Item=int
1>          ]
========== Build: 0 succeeded, 1 failed, 0 up-to-date, 0 skipped ==========

请帮助

Answer 1

你打电话

push2(a,i+1,r);

a是一个项目数组

void quicksort(Item a[],int l,int r)

但push2()期望重新获得STACK<int>

inline void push2(STACK<int>&s,int a,int b)

Answer 2

  void quicksort(Item a[],int l,int r){

       STACK<int> s(50);
       push2(a,l,r);

push2接受STACK，您提供了数组a。

不要自己实现堆栈，请使用std::stack。

Answer 3

push2将STACK<int> &作为第一个参数。尝试将其传递给它，而不是完全不同的类型。

Answer 4

在快速排序模板功能的定义中，在调用push2时替换a =＆gt;小号

#include <iostream>
 #include <cstdlib>
 using namespace std;
 template<class Item>
 class STACK{
 private:
     Item *a;int n;
 public:
     STACK(int maxN){

         a=new Item[maxN];n=0;

     }
     int empty()const {
         return n==0;

     }
     void push(Item item){
         a[n++]=item;
         }
    Item pop() {
         return a[--n];

    }


 };
 template<class Item>
 int partition (Item a[],int l,int r){

     int i=l-1;
     int j=r;
     Item v=a[r];
      for (;;){

           while (a[++i]<v);
           while (v<a[--j])  if (j==i) break;
            if (i>=j) break;
             Item t=a[i];
             a[i]=a[j];
             a[j]=t;
      }

       Item s=a[i];
        a[i]=a[r];
        a[r]=s;
        return i;
        }
 inline void push2(STACK<int>&s,int a,int b){
     s.push(b);
     s.push(a);
     }



 template<class Item>
 void quicksort(Item a[],int l,int r){

     STACK<int> s(50);
     push2(s,l,r);
     while (!s.empty()){
    int l=s.pop();
    int r=s.pop();
       if (r<=l) continue;
       int i=partition(a,l,r);
        if(i-1>r-1)
        { push2(s,l,i-1);  push2(s,i+1,r);
        }
        else{
            push2(s,i+1,r);
            push2(s,l,i-1);

        }
     }
 }

 int main(){

     int a[]={45,12,30,67,11,17,50,78};
     int n=sizeof(a)/sizeof(a[0]);
     quicksort(a,0,n-1);
      for (int i=0;i<n;i++)
          cout<<a[i]<< "  ";
      return 0;

 }

带堆栈的非递归快速排序

4 个答案: