public static int prims(int n, List<List<Integer>> edges, int start) {
    //USING PROVIDED DATA APPROACH
    
    Comparator<List<Integer>> comp = (l1, l2) -> {
        return l1.get(2) - l2.get(2);
    };
    
    Collections.sort(edges, comp);
    
    HashSet<Integer> set = new HashSet<>();
    set.add(start);
    
    int sumMin = 0;
    
    while (set.size() < n) {
        Iterator<List<Integer>> iter = edges.iterator();
            
        while (iter.hasNext()) {
            List<Integer> list = iter.next();
            
            int left = list.get(0);
            int right = list.get(1);
            int distance = list.get(2);
            
						//Using LinkedList might speed this up
						//Actual no need to remove already parsed list
						// to fit set limit
            if (set.contains(left) && set.contains(right)) {
                iter.remove();
                continue;
            }
                            
            if ((set.contains(left) && !set.contains(right)) 
                    || (!set.contains(left) && set.contains(right))) {
                sumMin += distance;
                set.add(left);
                set.add(right);
                break;
            }
        }   
    }
    
    return sumMin;
    
    /* CREATING SUMMARY ARRAY APPROACH
    int res = 0;
    
    int[][] grid = new int[n + 1][n + 1];
    
    for (List<Integer> list : edges) {
        int i = list.get(0);
        int j = list.get(1);
        int dis = list.get(2);
        
        grid[i][j] = dis;
        grid[j][i] = dis;
    }
    
    HashSet<Integer> set = new HashSet<>();

    set.add(start);
    
    while (set.size() < n) {
        TreeMap<Integer, Integer> map = new TreeMap<>();
        
        for (Integer i : set) {
            for (int j = 1; j < n + 1; j ++) {
                int curDis = grid[i][j];
                if (!set.contains(j) && curDis != 0) {
                    map.put(curDis, j);        
                }
            }
        }
        
        res += map.firstKey();
        set.add(map.firstEntry().getValue());
    }
    
    return res;
    */
}