Class Solution

KruskalsAlgorithm.java:1–29

class Solution {
    static int spanningTree(int V, int E, List<List<int[]>> adj) {
        // Code Here.
        //(u, v, weight)
        PriorityQueue<int[]> pq = new PriorityQueue<>(new Comparator<>(){
            public int compare(int pair1[], int pair2[]){
                return pair1[2] - pair2[2];
            }
        });
        // insert edges in pq
        for(int i=0;i<V;i++){
            for(int edges[] : adj.get(i)){
                pq.offer(new int[]{i,edges[0],edges[1]});
            }
        }
        DisjointSet dsu = new DisjointSet(V);
        int sum=0;
        while(!pq.isEmpty()){
            int object[] = pq.poll();
            int u = object[0];
            int v = object[1];
            int weight = object[2];
            if(dsu.unionBySize(u,v)){
                sum += weight;
            }
        }
        return sum;
    }
}


class DisjointSet {