next_permutation,pre_permutation,random_shuffle

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32767double 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;}