并查集Java实现（扁平化）

public class Main {

	public static int MAXN = 200001;

	public static int[] father = new int[MAXN];

	public static int n = 10;

	public static void build() {
		for (int i = 0; i <= n; i++) {
			father[i] = i;
		}
	}

	public static int find(int i) {
		if (i != father[i]) {
			father[i] = find(father[i]);
		}
		return father[i];
	}

	public static boolean isSameSet(int x, int y) {
		return find(x) == find(y);
	}

	public static void union(int x, int y) {
		father[find(x)] = find(y);
	}

}