1319. Number of Operations to Make Network Connected

class Solution {
    public int makeConnected(int n, int[][] connections) {
        if (connections.length < n - 1) {
            return -1;
        }
        
       
        UnionFind uf = new UnionFind(n);
        
       
        for (int[] connection : connections) {
            uf.union(connection[0], connection[1]);
        }
        
        
        int numComponents = uf.getCount();
        
        
        return numComponents - 1;
    }



class UnionFind {
    private int[] parent;
    private int[] rank;
    private int count;
    
    public UnionFind(int size) {
        parent = new int[size];
        rank = new int[size];
        count = size;
        for (int i = 0; i < size; i++) {
            parent[i] = i;
            rank[i] = 1;
        }
    }
    
    public int find(int p) {
        if (parent[p] != p) {
            parent[p] = find(parent[p]); 
        }
        return parent[p];
    }
    
    public boolean union(int p, int q) {
        int rootP = find(p);
        int rootQ = find(q);
        if (rootP == rootQ) {
            return false;
        }
        
        
        if (rank[rootP] > rank[rootQ]) {
            parent[rootQ] = rootP;
        } else if (rank[rootP] < rank[rootQ]) {
            parent[rootP] = rootQ;
        } else {
            parent[rootQ] = rootP;
            rank[rootP]++;
        }
        
        count--;
        return true;
    }
    
    public int getCount() {
        return count;
    }
    }
}