并查集之找祖先的模板

int find(int x){if (x==per[x])return x;return per[x]=find(per[x]);}//递归查找int find(int x){int r=x;while (r!=per[r])r=per[r];per[x]=r;return r; }//   int find(int x) { int r=x; while (r!=per[r]) r=per[r]; int i,j; i=x; while (i!=r) { j=per[r]; per[r]=r; i=j; } return r; }