684. Redundant Connection

class Solution {
    
    int[] parent;
    public int[] findRedundantConnection(int[][] edges) {
        int n = edges.length;
        parent = new int[n+1];
        
        //make each node the parent of itself
        for(int i = 0; i <=n; i++) parent[i] = i;
        
        //Loop on all edges
        for(int[] edge : edges) {
            if(find(edge[0]) == find(edge[1])) return edge;
            union(edge[0], edge[1]);
        }
        
        return null;
        
    }
    
    
    int find(int node) {
        while(parent[node] != node) {
            node = parent[node];
        }
        
        return node;
    }
    
    void union (int i, int j) {
        int iRoot = find(i);
        int jRoot = find(j);
        
        if(iRoot != jRoot) {
            parent[jRoot] = iRoot;
        }
        
    }
    
}