并查集板子

build方法

void build()
{for(int i=1;i<=maxn;i++)father[i]=i;
}

find方法

int find(int x)
{if(x!=father[x]){father[x]=father[find(x)];}return father[x];
}

merge方法

void merge(int x,int y)
{if(find(x)!=find(y)){father[find(x)]=find(y);}
}