学步园

直接代码：

//next_permutation prev_permutation
#include<iostream>
#include<string>
#include<vector>
#include<algorithm>
#include<functional>
using namespace std;
int main(){
	int a[]={1,2,3};
	vector<int>v(a,a+3);
	copy(v.begin(),v.end(),ostream_iterator<int>(cout," "));
	cout<<endl;
	while(next_permutation(v.begin(),v.end())){
		copy(v.begin(),v.end(),ostream_iterator<int>(cout," "));
		cout<<endl;
	}
	//调用了next_permutation之后
	cout<<"after next_permutation:"<<endl;
	copy(v.begin(),v.end(),ostream_iterator<int>(cout," "));
	cout<<endl;
	cout<<"***********************"<<endl;
	while(prev_permutation(v.begin(),v.end())){
		copy(v.begin(),v.end(),ostream_iterator<int>(cout," "));
		cout<<endl;
	}
	cout<<"after prev_permutation:"<<endl;
	copy(v.begin(),v.end(),ostream_iterator<int>(cout," "));
	cout<<endl;
	while(prev_permutation(v.begin(),v.end())){
		copy(v.begin(),v.end(),ostream_iterator<int>(cout," "));
		cout<<endl;
	}
	system("pause");
	return 0;
}

//重排元素
#include<iostream>
#include<string>
#include<vector>
#include<algorithm>
#include<functional>
#include<ctime>
using namespace std;

class MyRandom{
public:
	ptrdiff_t operator()(ptrdiff_t max){//RAND_MAX是一个常量32767
		double temp;
		temp=static_cast<double>(rand())/static_cast<double>(RAND_MAX);
		return static_cast<ptrdiff_t>(temp*max);
	}
};
int main(){
	int a[]={1,2,3,4,5,6,7,8,9,10};
	vector<int>v(a,a+10);
	vector<int>vv(a,a+10);
	random_shuffle(v.begin(),v.end());//只能一次，以后都是这个排序
	for(vector<int>::iterator iter=v.begin();iter!=v.end();++iter){
		cout<<*iter<<" ";
	}
	cout<<endl;
	srand(unsigned(time(NULL)));
	MyRandom suiji;
	random_shuffle(vv.begin(),vv.end(),suiji);//现在实现了真正的随机
	for(vector<int>::iterator it=vv.begin();it!=vv.end();++it){
		cout<<*it<<" ";
	}
	cout<<endl;
	system("pause");
	return 0;
}