快排的非递归实现

最新推荐文章于 2024-12-28 23:34:57 发布

原创最新推荐文章于 2024-12-28 23:34:57 发布 · 417 阅读

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CC 4.0 BY-SA版权

http://www.360doc.com/content/14/0516/13/17064216_378214717.shtml

#include<iostream>
#include<stack>
using namespace std;
int partion(int* a, int low, int high){
int temp=a[low];
while(low<high){
while(low<high && a[high]>temp)
--high;
a[low]=a[high];
while(low<high && a[low]<temp)
++low;
a[high]=a[low];
}
a[low]=temp;
return low;
}

void qsort(int* a, int low, int high){
if(!a|| low>=high)
return;
stack<int> q;
if(low<high){
int mid=partion(a,low,high);
if(mid>low){
q.push(low);
q.push(mid-1);
}
if(mid<high){
q.push(mid+1);
q.push(high);
}
while(!q.empty()){
int p1=q.top();
q.pop();
int p2=q.top();
q.pop();
mid=partion(a,p2,p1);
if(mid>p2){
q.push(p2);
q.push(mid-1);
}
if(mid<p1){
q.push(mid+1);
q.push(p1);
}
}

}

}

int main(){
int a[]={1,3,5,2,0,8};
qsort(a,0,5);
for(int i=0;i<6;++i)
cout<<a[i]<<' ';
cout<<endl;
return 0;
}

注意：这里非递归算法的速度低于递归算法，由于stl 栈的效率低