static class Bridge {

int x;

int y;

int cost;

Bridge(int x, int y, int cost){

this.x = x;

this.y = y;

this.cost = cost;

}

}

public static void main(String[] args) {

int n = 4;

int[][] costs = {{0,1,1},{0,2,2},{1,2,5},{1,3,1},{2,3,8}};

System.out.println(solution(n,costs));

}

static int solution(int n, int[][] costs) {

int length = costs.length;

Bridge[] bridgeArr = new Bridge[length];

for(int i=0; i<length; i++){

if(costs[i][2] == 0){

continue;

}

bridgeArr[i] = new Bridge(costs[i][0],costs[i][1],costs[i][2]);

}

Arrays.sort(bridgeArr, Comparator.comparingInt(o -> o.cost));

int[] parent = new int[length+1];

for(int i=1; i<length+1; i++){

parent[i] = i;

}

int minCost = 0;

int line = 0;

for(Bridge bridge : bridgeArr){

if(line == n-1){ //간선수는 n-1개

break;

}

if(find(parent, bridge.x) != find(parent, bridge.y)){

union(parent,bridge.x,bridge.y);

minCost += bridge.cost;

line++;

}

}

return minCost;

}

static int find(int[] parent, int num){

if(parent[num] == num){

return parent[num];

}

return parent[num] = find(parent,parent[num]);

}

static void union(int[] parent,int num1, int num2){

if(num1 == num2){

return;

}

if(num1 > num2){

parent[num1] = num2;

}else{

parent[num2] = num1;

}

}