zju 1089_Lotto

题目：

Lotto
Time Limit: Java: 2000 ms / Others: 2000 ms

Memory Limit: Java: 65536 KB / Others: 65536 KB

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Description

In a Lotto I have ever played, one has 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
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 k integers, specifying the set S, will follow in ascending order.
Input will be terminated by a value of zero (0) for k.
Output
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

题目大意：
题中会给定一个k ，若是k > 0， 这会给出k个数然后我们需要从这k个不同的数里面选6个数输出，要求一个输出序列 要从小到大进行输出，若有多种可能的情况 按字典序从小达到进行输出。

解题思路：
刚开始我是想着用搜索来写，但感觉有些麻烦。然后其实每个一个序列中的第一的数只会从 1 - k - 5 的下标的数中去选，所以我们可以直接这样模拟就可以输出了。

AC代码：

#include <iostream>
#include <cstdio>

using namespace std;

const int maxn = 55;

int main(void) {
//	freopen("in.txt", "r", stdin);
	
	int k, f = 0;
	while(scanf("%d", &k) != EOF && k) {
		if(f) puts(""), puts("");
		f = 1;
		int p[maxn];
		for(int i = 1; i <= k; i ++) scanf("%d", &p[i]);
		
		int i = k - 5;
		
		for(int a = 1; a <= i; a ++)
		for(int b = a + 1; b <= i + 1; b ++)
		for(int c = b + 1; c <= i + 2; c ++)
		for(int d = c + 1; d <= i + 3; d ++)
		for(int e = d + 1; e <= i + 4; e ++)
		for(int f = e + 1; f <= i + 5; f ++)
		if(a == i && b == i + 1 && c == i + 2 && d == i + 3 && e == i + 4 && f == i + 5) 
			printf("%d %d %d %d %d %d", p[a], p[b], p[c], p[d], p[e], p[f]);
		else printf("%d %d %d %d %d %d\n", p[a], p[b], p[c], p[d], p[e], p[f]);
		
	}
	
//	fclose(stdin);
	return 0;
}