[ACM训练题]算法入门 - 记录表法解题

#include 
#include 
using namespace std;

int main()
{
    int n, k;
    cin >> n >> k;
    int p[n], ret = 0;
    for (int i = 0; i < n; ++i)
        cin >> p[i];
    sort(p, p + n); //给数组排序，便于计算最小预算
    int map[n]{0};  //若有幻钾则变为1
    for (int l = 0; l < n; ++l)
    {
        int r = l + 1;
        while (r != n)
        {
            if ((p[l] + p[r]) % k == 0)
            {
                map[l] = 1;
                map[r] = 1;
            }
            r++;
        }
    }
    int flag = 1;
    for (int i = 0; i < n; ++i)
    {
        if (map[i] == 1 && flag) //计算第一个存在幻钾的地区
        {
            ret += p[i] * p[i];
            flag = 0;
        }
        if (map[i] == 0)
        {
            ret += p[i] * p[i];
        }
    }
    cout << ret << endl;
    return 0;
}