public class Solution {
	 public int solution(int n, int[][] costs) {

	    	int answer = 0;
	    	int[] parent = new int[n];


	    	for(int i =0; i < n; i++) {
	    		parent[i] = i;
	    	}


	    	//오름차순 정렬
	    	Arrays.sort(costs,(o1,o2)-> {
	    		return o1[2] -o2[2];
	    	});


	    	for(int[]t : costs ) {

	    		if(!checkUnion(parent, t[0], t[1]) ) {
	    			answer += t[2];
	    			setUinon(parent, t[0], t[1]);
	    		}

	    	}
	        return answer;
	    }

	    //부모를 찾는다.
	    public int getParent(int[] parent, int a) {    	
			if(parent[a] == a ) {
				return a;
			}else {
			  return getParent(parent, parent[a]);
			}
	    }

        //두 노드를 연결
	    public void setUinon(int[] parent, int a, int b) {
	    	a = getParent(parent, a);
	    	b = getParent(parent, b);

	    	if(a < b) {
	    		parent[b] = a;
	    	}else {
	    		parent[a] = b;
	    	}
	    }

        //부모가 같은지 체크(연결되어 있는지 확인)
	    public boolean checkUnion(int[] parent, int a, int b) {
	    	a = getParent(parent, a);
	    	b = getParent(parent, b);

	    	return a==b;
	    }
}