UVa 406 Prime Cuts

寫得時候頭腦不是很清楚
有點亂，不夠漂亮，只能算剛好AC而已

	/**
	* UVa 406 Prime Cuts (AC)
	* Author: chchwy
	* Last Modified: 2009.11.22
	*/
	#include<iostream>
	#include<vector>
	using namespace std;
	enum {MAX = 1001};
	char p[MAX]; //prime=0, not prime=1
	void shieve()
	{
	p[0] = 1;
	p[1] = 0; //本題1算質數
	for (int i = 2; i * i < MAX; ++i)
	{
	if (p[i] == 1)
	continue;
	for (int j = i * i; j < MAX; j += i)
	p[j] = 1;
	}
	}
	int main()
	{
	shieve();
	int N, C;
	while (scanf("%d %d", &N, &C) == 2)
	{
	printf("%d %d:", N, C);
	vector<int> prime;
	for (int i = 1; i <= N; ++i)
	if (p[i] == 0)
	prime.push_back(i);
	int cuts = (prime.size() % 2 == 0) ? C * 2 : C * 2 - 1;
	if (cuts > prime.size())
	cuts = prime.size();
	int begin = (int)(prime.size() - cuts) / 2;
	if (begin < 0) begin = 0;
	for (int i = begin; i < begin + cuts; ++i)
	printf(" %d", prime[i]);
	printf("\n\n");
	}
	return 0;
	}

view raw 406.cpp hosted with ❤ by GitHub