poj1833 全排列（卡时间）

/*
Time:2019.11.8
Author: Goven
type：全排列 
err:超时 Time Limit Exceeded 
ref: https://www.cnblogs.com/coolwind-sea/archive/2012/04/17/2454313.html
https://blog.csdn.net/qq_40421671/article/details/89073418
知识点 ：1.next_permutation()到达最后一个排列组合时，再调用会返回false，但是组合会重新循环 
            时间效率不高
        2.输出用copy，效率较高 
*/

//错误版--超时 
#include<iostream>
#include<algorithm>
using namespace std;

int a[1050];

int main()
{
    int t, n, k;
    cin >> t;
    while (t--) {
        cin >> n >> k;
        for (int i = 0; i < n; i++) {
            cin >> a[i];
        }
        while (k && next_permutation(a, a + n)) k--;
        if (k > 0) {
            sort(a, a + n);
            k--;
            while (k && next_permutation(a, a + n)) k--;
        }
        cout << a[0];
        for (int i = 1; i < n; i++) {
            cout << " " << a[i];
        }
        cout << endl;
    }
    return 0;
}

//正确 
#include<iostream>
#include<algorithm>
#include<iterator>
using namespace std;

int a[1050];

int main()
{
    int t, n, k;
    scanf("%d", &t);
    while (t--) {
        scanf("%d%d", &n, &k);
        for (int i = 0; i < n; i++) {
//          cin >> a[i];//err1
            scanf("%d", &a[i]); 
        }
        for (int i = 0; i < k ; i++) {
            next_permutation(a, a + n);
        }
        copy(a, a + n - 1, ostream_iterator<int>(cout, " "));
        cout << a[n - 1] << endl; 
    }
    return 0;
}