代码(AC):
(此题和小鑫的城堡那题大同小异,只是输入上要有所注意,-1 -1结束总输入,0 0结束一组输入,我
是先输入两个数,做判断后在引出后面的一系列数,再次判断,再输入。这样忽略了一个问题,一组数据
前两个数是0 0怎么办,那得单独考虑,输出Yes即可。)
#include <stdio.h>
#include <string.h>
int bin[100001];
int wz[100001];
int find(int x)
{
int r = x;
while (bin[r]!=r)
{
r=bin[r];
}
int i = x;
while(bin[i]!=r)
{
int j;
j = bin[i];
bin[i] = r;
i = j;
}
return r;
}
int merge(int x,int y)
{
int fx,fy;
fx = find(x);
fy = find(y);
if(fx != fy)
{
bin[fy] = fx;
return 1;
}
else
return 0;
}
int main ()
{
int x=0,y=0,flag=0;
int i=0,t,j=0;
while(scanf("%d%d",&x,&y))
{ if(x==-1&&y==-1) break;
if(x==0&&y==0) {printf("Yes\n"); continue;}
memset(wz,0,sizeof(wz));
memset(bin,0,sizeof(bin));
for (i = 0; i < 100001; i++)
{
bin[i] = i;
}
merge(x , y);
wz[x] = 1;
wz[y] = 1;
t = 1;
flag = 1;
while(scanf("%d%d",&x,&y))
{
if(x==0&&y==0)
break;
if (wz[x] == 0)
{
t++;
wz[x] = 1;
}
if (wz[y] == 0)
{
t++;
wz[y] = 1;
}
int z = merge(x,y);
if (z == 1)
t--;
else
flag = 0;
}
if (flag == 1&&t==1)
printf ("Yes\n");
else
printf ("No\n");
}
return 0;
}