• + 4 comments

    My Java solution

    public class Solution {
        
        static class DisjointSet {
            int[] parent;
            int[] size;
            
            DisjointSet(int n) {
                parent = new int[n+1];
                size = new int[n+1];
                for(int i = 0; i <= n; i++) {
                    parent[i] = i;
                    size[i] = 1;
                }
            }
            public boolean connected(int p, int q) {
                return find(p) == find(q);
            }
            
            private int find(int p) {
                int root = p;
                while (root != parent[root]) {
                	parent[root]=parent[parent[root]];
                	root=parent[root];
                }
                /*while (root != parent[root])
                    root = parent[root];
                while (p != root) {
                    int newp = parent[p];
                    parent[p] = root;
                    p = newp;
                }*/
                return root;
            }
                
            public void union(int p, int q) {
                int rootP = find(p);
                int rootQ = find(q);
                if (rootP == rootQ) return;
                
                if (size[rootP] < size[rootQ]) {
                    parent[rootP] = rootQ;                
                    size[rootQ] += size[rootP];
                }
                else {
                    parent[rootQ] = rootP;
                    size[rootP] += size[rootQ];
                }
            }
            
            public int size(int p) {
                int rootP = find(p);
                return size[rootP];
            }
        }
        
        public static void main(String[] args) {
            Scanner sc = new Scanner(System.in);
            int n = sc.nextInt();
            int q = sc.nextInt();
            DisjointSet dSet = new DisjointSet(n);
            for(int i = 0; i < q; i++) {
                String op = sc.next();
                switch(op) {
                    case "Q" :
                        int p = sc.nextInt();
                        System.out.println(dSet.size(p));
                        break;
                    case "M" :
                        int a = sc.nextInt();
                        int b = sc.nextInt();
                        dSet.union(a, b);
                        break;
                }
            }
        }
    }