code 防止爆棧空間
int find(int x){
int p=x;
while(p!=fa[p])
p=fa[p];
while(x!=p){
int tmp=fa[x];
fa[x]=p;
x=tmp;
}
return x;
}
int find(int x){
int p=x;
while(p!=fa[p])
p=fa[p];
while(x!=p){
int tmp=fa[x];
fa[x]=p;
x=tmp;
}
return x;
}