3065043_ac_76ms_464k.c

北大大牛代码 1240道题的原代码 超级权威

#include <stdio.h>
#include <string.h>

int p[201][201];
int cnt[40001];

int n, m;

int main()
{
	int i, j, b, k, ans;

	scanf("%d%d",&n,&m);
	for (i = 1; i <= n; i++)
	{
		for (j = i+1; j <= n; j++)
		{
			p[i][j] = 1;
		}
	}
	for (k = 1,b = 0; k <= m+1; k++,b=!b)
	{
		if (b==0)
		{
			memset(cnt,0,sizeof(cnt));
			for (i = 1; i <= n; i++)
			{
				for (j = i+1; j <= n; j++)
				{
					if (p[i][j]==1)
					{
						cnt[i+j]++;
					}
				}
			}
			for (i = 1; i <= n; i++)
			{
				for (j = i+1; j <= n; j++)
				{
					if (p[i][j]==1&&((cnt[i+j]==1)^(k==m+1)))
					{
						p[i][j] = 0;
					}
				}
			}
		}
		else
		{
			memset(cnt,0,sizeof(cnt));
			for (i = 1; i <= n; i++)
			{
				for (j = i+1; j <= n; j++)
				{
					if (p[i][j]==1)
					{
						cnt[i*j]++;
					}
				}
			}
			for (i = 1; i <= n; i++)
			{
				for (j = i+1; j <= n; j++)
				{
					if (p[i][j]==1&&((cnt[i*j]==1)^(k==m+1)))
					{
						p[i][j] = 0;
					}
				}
			}
		}
	}
	ans = 0;
	for (i = 1; i <= n; i++)
	{
		for (j = i+1; j <= n; j++)
		{
			ans += p[i][j];
		}
	}
	printf("%d\n",ans);
	for (i = 1; i <= n; i++)
	{
		for (j = i+1; j <= n; j++)
		{
			if (p[i][j])
			{
				printf("%d %d\n",i,j);
			}
		}
	}
	return 0;
}