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// @Title: 移除最多的同行或同列石头 (Most Stones Removed with Same Row or Column)
// @Author: 15816537946@163.com
// @Date: 2021-01-16 10:55:56
// @Runtime: 20 ms
// @Memory: 6.7 MB
type unionFind struct {
	parent map[int]int
	cnt    int
}

func NewUnionFind() *unionFind {
	return &unionFind{
		parent: make(map[int]int),
	}
}

func (u *unionFind) getCount() int {
	return u.cnt
}

func (u *unionFind) find(x int) int {
	if _, exists := u.parent[x]; !exists {
		u.parent[x] = x
		u.cnt++
	}

	if x != u.parent[x] {
		u.parent[x] = u.find(u.parent[x])
	}
	return u.parent[x]
}

func (u *unionFind) union(x, y int) {
	rootX, rootY := u.find(x), u.find(y)
	if rootX == rootY {
		return
	}
	u.parent[rootX] = rootY
	u.cnt--
}

func removeStones(stones [][]int) int {
	uf := NewUnionFind()

	for _, s := range stones {
		uf.union(s[0]+10001, s[1])
	}

	return len(stones) - uf.getCount()
}