next_permutation();

可以用于可重, 或者不可重集, 寻找下一个排列.

时间复杂度尚不明.

//适用于不可重和可重集的排列.# include <iostream># include <algorithm>using namespace std;int a[1003], n;int main(){    cin >> n;    for (int i = 0; i < n; ++i )        cin >> a[i];    sort(a, a+n);    do    {        for(int i = 0; i < n; ++i)            cout << a[i] << ‘ ‘;        cout << endl;    } while( next_permutation(a, a+n) );    return 0;}