Beauty Pageant（CF-246C）

Problem Description

General Payne has a battalion of n soldiers. The soldiers' beauty contest is coming up, it will last for k days. Payne decided that his battalion will participate in the pageant. Now he has choose the participants.

All soldiers in the battalion have different beauty that is represented by a positive integer. The value ai represents the beauty of the i-th soldier.

On each of k days Generals has to send a detachment of soldiers to the pageant. The beauty of the detachment is the sum of the beauties of the soldiers, who are part of this detachment. Payne wants to surprise the jury of the beauty pageant, so each of k days the beauty of the sent detachment should be unique. In other words, all k beauties of the sent detachments must be distinct numbers.

Help Payne choose k detachments of different beauties for the pageant. Please note that Payne cannot just forget to send soldiers on one day, that is, the detachment of soldiers he sends to the pageant should never be empty.

Input

The first line contains two integers n, k (1 ≤ n ≤ 50; 1 ≤ k ≤  ) — the number of soldiers and the number of days in the pageant, correspondingly. The second line contains space-separated integers a1, a2, ..., an (1 ≤ ai ≤ 107) — the beauties of the battalion soldiers.

It is guaranteed that Payne's battalion doesn't have two soldiers with the same beauty.

Output

Print k lines: in the i-th line print the description of the detachment that will participate in the pageant on the i-th day. The description consists of integer ci (1 ≤ ci ≤ n) — the number of soldiers in the detachment on the i-th day of the pageant and ci distinct integers p1, i, p2, i, ..., pci, i — the beauties of the soldiers in the detachment on the i-th day of the pageant. The beauties of the soldiers are allowed to print in any order.

Separate numbers on the lines by spaces. It is guaranteed that there is the solution that meets the problem conditions. If there are multiple solutions, print any of them.

Examples

Input

3 3
1 2 3

Output

1 1
1 2
2 3 2

Input

2 1
7 12

Output

1 12 

题意：有 n 个人，每个人有一个价值，现在要进行 k 天的比赛，要求每天选择至少 1 个人，使得这些人的价值和不同，输出每天的选择的人的个数与这些人的价值

思路：将所有人都降序排列后，首先依次单个输出，然后再两个一组输出，三个一组输出，依次类推，直到输出的组数与 k 相等为止

Source Program

#include<iostream>
#include<cstdio>
#include<cstdlib>
#include<string>
#include<cstring>
#include<cmath>
#include<ctime>
#include<algorithm>
#include<utility>
#include<stack>
#include<queue>
#include<vector>
#include<set>
#include<map>
#include<bitset>
#define PI acos(-1.0)
#define INF 0x3f3f3f3f
#define LL long long
#define Pair pair<int,int>
const double EPS = 1E-10;
const int MOD = 1E9+7;
const int N = 100000+5;
const int dx[] = {-1,1,0,0,-1,-1,1,1};
const int dy[] = {0,0,-1,1,-1,1,-1,1};
using namespace std;

int a[N];
bool cmp(int x,int y){
    return x>y;
}
int main(){
    int n,k;
    scanf("%d%d",&n,&k);
    for(int i=1;i<=n;i++)
        scanf("%d",&a[i]);
    sort(a+1,a+1+n,cmp);

    int len=0,num=0;
    bool flag=true;
    while(flag){
        len++;
        for(int i=len;i<=n;i++){
            printf("%d ",len);
            for(int j=1;j<len;j++)
                printf("%d ",a[j]);
            printf("%d\n",a[i]);
            num++;
            if(num==k){
                flag=false;
                break;
            }
        }
    }

    return 0;
}