求纠错：用STL容器vector和算法partition实现快速排序功能

[davyjones2010]

自己的代码，但是运行不成功，找不到问题所在，还望高手指点迷津，晚生这厢有礼了···
#include<iostream>
#include<vector>
#include<algorithm>
#include<functional>
using namespace std;
typedef vector<int> VI;
typedef vector<int>::iterator VIT;
void qsort(VIT a,VIT b)
{
if(*a<*b)
{
VIT t=a;
t=partition(a,b,bind2nd(less<int>(),*t));
if(a<t-1)
qsort(a,t-1);
if(b>t+1)
qsort(t+1,b);
}
}
int main()
{
int a;
VI v_in;
VIT start,end,it;
start=v_in.begin();
end=v_in.end();
cout<<"Input 5 numbers:";
for(int i=0;i<5;i++)
{
cin>>a;
v_in.push_back(a);
}
qsort(start,end);
for(it=start;it!=end;it++)
{
cout<<*it<<' ';
}
cout<<endl;
return 0;
}

[jackyjkchen]

算法里直接有sort，何必脱裤子放屁呢？

[davyjones2010]

呵呵 ，这是老师布置的作业，没办法的啊，汗

[taodm]

自己一次次打印出qsort的输入输出数据来找规律呗。

[oyster2008]

#include<iostream>
#include<vector>
#include<algorithm>
#include<functional>
using namespace std;
typedef vector<int> VI;
typedef vector<int>::iterator VIT;
void qsort(VIT a,VIT b)
{
        if( a < b - 1 )
        {
                VIT t=a;
                t=partition(a+1,b,bind2nd(less<int>(),*t));
                swap(*a,*(t-1));
                qsort(a,t-1);
                qsort(t,b);
        }
}
int main()
{
        int a;
        VI v_in;
        VIT start,end,it;
        cout<<"Input 5 numbers:";
        for(int i=0;i<5;i++)
        {
                cin>>a;
                v_in.push_back(a);
        }
        start=v_in.begin();
        end=v_in.end();
        qsort(start,end);
        for(it=v_in.begin();it!=v_in.end();it++)
        {
                cout<<*it<<' ';
        }
        cout<<endl;
        return 0;
}

[mstlq]

简单示范

#include<iostream>
#include<vector>
#include<algorithm>
#include<functional>
using namespace std;
typedef vector<int> VI;
typedef vector<int>::iterator VIT;

void qsort(VIT a, VIT b)
{
    if (a < b)
    {
        VIT t = partition(a, b, bind2nd(less<int>(), *a));
        qsort(a, t);
        if (*t == *a) t = a + 1;
        qsort(t , b);
    }
}
int main()
{
    int a;
    VI v_in;
    VIT it;
    cout << "Input 5 numbers:";
    for (int i = 0; i < 5; i++)
    {
        cin >> a;
        v_in.push_back(a);
    }
    qsort(v_in.begin(), v_in.end());
    for (it = v_in.begin(); it != v_in.end(); it++)
    {
        cout << *it << ' ';
    }
    cout << endl;
    return 0;
}

[oyster2008]

qsort改成这样，安全一些

void qsort(VIT a,VIT b)
{
        if( a < b  )
        {
                VIT t=a;
                t=partition(a+1,b,bind2nd(less<int>(),*t));
                swap(*a,*(t-1));
                qsort(a,t-1);
                qsort(t,b);
        }
}