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

#define MAX 50002

long a[MAX];

int main()
{
	long i,j,k;
	long n,m;
	long tot;
	long x,y;
	
		memset(a,0,sizeof(a));
		scanf("%ld %ld",&n,&m);
		for (i=1;i<=m;i++)
		{
			scanf("%ld %ld",&x,&y);
			if (a[x]<y)
				a[x]=y;
		}

		i=1;
		tot=0;
		k=a[1];
		do
		{
			tot++;
			if (k>=n)
				break;

			j=k;
			while (i<=k)
			{
				if (a[i]>j)
					j=a[i];
				i++;
			}
			k=j;

		}while (1);


		printf("%ld\n",tot);
	return 0;
}

• Re:还有我这个，why wa? (622) pxwanfeng 2005-09-27 19:37:28
• Re:还有我这个，why wa? (65) pxwanfeng 2005-09-27 19:38:24
  • Re:还有我这个，why wa? (135) hjin 2007-08-02 14:27:37