UVa 441 Lotto

想法：
    排列組合中的組合，因此每次挑選的時候只能比之前挑的數字還要大，用遞迴做Backtraking，詳細見底下code:

	#include <cstdio>
	#include <algorithm>
	using namespace std;
	int N, S[100], choosed[100], ans[100];
	void func(int len, int pos)
	{
	if (len == 6){
	for (int i = 0; i < 5; ++i)
	printf("%d ", ans[i]);
	printf("%d\n", ans[5]);
	return;
	}
	for (int i = pos; i < N; ++i) {
	if (!choosed[i]) {
	choosed[i] = 1;
	ans[len] = S[i];
	func(len+1, i + 1);
	choosed[i] = 0;
	}
	}
	}
	int main()
	{
	int Case = 0;
	while (scanf("%d", &N) && N) {
	if (Case++) printf("\n");
	for (int i = 0; i < N; ++i){
	scanf("%d", &S[i]);
	choosed[i] = 0;
	}
	func(0,0);
	}
	}

view raw [UVa] 441 Lotto.cpp hosted with ❤ by GitHub