并查集路径压缩

递归方法路径压缩：

int find(int x)

{

if(x!=father[x])

father[x]=find(father[x]);

return father[x];

}

上面代码可能会RE；建议用下面的代码：

int findset(int x)

{

int r = x;

while(father[r]!=r) ///查找跟节点

r = father[r]; ///找到根节点，用r记录

int i = x,j;

while(i != r) ///非递归路径压缩

{

j = father[i]; ///用j暂时存father[i]的父节点

father[i] = r; ///father[i]指向跟节点

i = j; ///i移到父节点

}

return r; ///返回根节点的值

}