fix: changed to pointer receivers

Author: soondubu137

graph/unionfind.go

@@ -34,7 +34,7 @@ func NewUnionFind(s int) UnionFind {
 
 // Find finds the root of the set to which the given element belongs.
 // It performs path compression to make future Find operations faster.
-func (u UnionFind) Find(q int) int {
+func (u *UnionFind) Find(q int) int {
 	if q != u.parent[q] {
 		u.parent[q] = u.Find(u.parent[q])
 	}
@@ -43,7 +43,7 @@ func (u UnionFind) Find(q int) int {
 
 // Union merges the sets, if not already merged, to which the given elements belong.
 // It performs union by rank to keep the tree as flat as possible.
-func (u UnionFind) Union(p, q int) {
+func (u *UnionFind) Union(p, q int) {
 	rootP := u.Find(p)
 	rootQ := u.Find(q)