#include <iostream>
#include <algorithm>

using namespace std;

int main()
{
    int n, k;
    int a[100];

    cin >> n >> k;
    for (int i = 0; i < n; i ++ ) cin >> a[i];

    reverse(a, a + k);              //要用到<algorithm>库函数
    reverse(a + k, a + n);
    reverse(a, a + n);              //翻转函数，以a[0]和a[n]为首尾

     for (int i = 0; i < n; i ++ )
        for (int j = i + 1; j < n; j ++ )
            if (a[i] > a[j])
                swap(a[i], a[j]);   //要用到<algorithm>库函数，交换两个数组元素

    for (int i = 0; i < n; i ++ ) cout << a[i] << ' ';
    cout << endl;

    return 0;
}

练习题5：计算 2 的N 次方。N≤10000

#include <iostream>
#include <algorithm>

using namespace std;

int main()
{
    int a[10000], size = 1, n;
    a[0] = 1;

    cin >> n;
    while (n -- )
    {
        int t = 0;
        for (int i = 0; i < size; i ++ )            //高精度算法
        {
            t += a[i] * 2;
            a[i] = t % 10;
            t /= 10;
        }
        if (t) a[size ++ ] = t;
    }

    for (int i = size - 1; i >= 0; i -- ) cout << a[i];
    cout << endl;

    return 0;
}