1028.txt

北大ACM题目例程 详细的解答过程 程序实现 算法分析

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

char name[200][210], n;

int st1[200],st2[200],s1,s2,cur;

int main()
{
	char cmd[100];

	strcpy( name[0], "http://www.acm.org/" );
	n = 1; s1 = 0; s2 = 0;cur = 0;

	while(1)
	{
		scanf( "%s", cmd );
		if( cmd[0] == 'Q' ) break;
		switch( cmd[0] )
		{
			case 'V': scanf( "%s", name[n] );
				st1[s1++] = cur; cur = n;
				s2 = 0;
				printf( "%s\n", name[n++] );
				break;
			case 'B': if( s1 == 0 ){  printf( "Ignored\n" ); break; }
				st2[s2++] = cur; cur = st1[--s1];
				printf( "%s\n", name[cur] );
				break;
			case 'F': if( s2 == 0 ){  printf( "Ignored\n" ); break; }
				st1[s1++] = cur; cur = st2[--s2];
				printf( "%s\n", name[cur] );
				break;
			default: break;
		}
	}

	return 0;
}