Lotto-(打印排列)

Lotto

In the German Lotto you have to select 6 numbers from the set {1,2,...,49}.

A popular strategy to play Lotto - although it doesn't increase your chance of winning - is to select a subset S containing k (k>6) of these 49 numbers, and then play several games with choosing numbers only from S.

For example, for k=8 and S = 1,2,3,5,8,13,21,34 there are 28 possible games: [1,2,3,5,8,13], [1,2,3,5,8,21], [1,2,3,5,8,34], [1,2,3,5,13,21], ..., [3,5,8,13,21,34].

Your job is to write a program that reads in the number k and the set S and then prints all possible games choosing numbers only from S.

Input Specification

The input file will contain one or more test cases.

Each test case consists of one line containing several integers separated from each other by spaces. The first integer on the line will be the number k (6 < k < 13). Then k integers, specifying the set S, will follow in ascending order.

Input will be terminated by a value of zero (0) for k.

Output Specification

For each test case, print all possible games, each game on one line.

The numbers of each game have to be sorted in ascending order and separated from each other by exactly one space. The games themselves have to be sorted lexicographically, that means sorted by the lowest number first, then by the second lowest and so on, as demonstrated in the sample output below.

The test cases have to be separated from each other by exactly one blank line. Do not put a blank line after the last test case.

Sample Input

7 1 2 3 4 5 6 7
8 1 2 3 5 8 13 21 34
0

Sample Output

1 2 3 4 5 6
1 2 3 4 5 7
1 2 3 4 6 7
1 2 3 5 6 7
1 2 4 5 6 7
1 3 4 5 6 7
2 3 4 5 6 7

1 2 3 5 8 13
1 2 3 5 8 21
1 2 3 5 8 34
1 2 3 5 13 21
1 2 3 5 13 34
1 2 3 5 21 34
1 2 3 8 13 21
1 2 3 8 13 34
1 2 3 8 21 34
1 2 3 13 21 34
1 2 5 8 13 21
1 2 5 8 13 34
1 2 5 8 21 34
1 2 5 13 21 34
1 2 8 13 21 34
1 3 5 8 13 21
1 3 5 8 13 34
1 3 5 8 21 34
1 3 5 13 21 34
1 3 8 13 21 34
1 5 8 13 21 34
2 3 5 8 13 21
2 3 5 8 13 34
2 3 5 8 21 34
2 3 5 13 21 34
2 3 8 13 21 34
2 5 8 13 21 34
3 5 8 13 21 34

题意:输入n,再从小到大输入n个数,要求输出这n个数中任意6个数,但要从小到大

(相当于输出全排列中的升序)

打印全排列(暴力-枚举排列)这个链接是关于输出n个数的全排列,如果去掉有降序部分的,就是本题代码...

#include<stdio.h>
int c[20],A[1000000];
void print_permutation(int n,int *A,int cur)
{
    int i,j;
    if(cur==6)      //当A数组中元素达到cur个时,就输出
    {
        for(i=0; i<5; i++)printf("%d ",A[i]);
        printf("%d\n",A[5]);
    }
    else for(i=0; i<n; i++)
        {
            int ok=1;
            for(j=0; j<cur; j++)
                if(A[j]>=c[i]) ok=0;    //如果c[i]已经A数组里出现过,或者A数组里存在某个元素大于c[i],则c[i]就不能被选作A[cur]
            if(ok)      //如果c[i]既没有出现过,也比A数组中所有元素大,就将c[i]添加至A数组末尾
            {
                A[cur]=c[i];
                print_permutation(n,A,cur+1);
            }
        }

}
int main()
{
    int n,i,v=0;
    while(scanf("%d",&n)!=EOF&&n!=0)
    {
        if(v==1)
        {
           printf("\n");
        }
        v=1;
        for(i=0;i<n;i++)
            scanf("%d",&c[i]);
        print_permutation(n,A,0);
    }
}