1129. Shortest Path with Alternating Colors

class Solution {
    public int[] shortestAlternatingPaths(int n, int[][] redEdges, int[][] blueEdges) {
        List[] adj = new ArrayList[n];
        for(int i=0;i<n;i++){
            adj[i] = new ArrayList<>();
        }
        for(int[] red:redEdges){
            adj[red[0]].add(new int[]{red[1],0});
        }
        for(int[] blue:blueEdges){
            adj[blue[0]].add(new int[]{blue[1],1});
        }

        Queue<int[]> queue = new LinkedList<>();
        int[] res = new int[n];
        Arrays.fill(res,-1);
        res[0]=0;
        boolean[][] v = new boolean[n][2];

        queue.add(new int[]{0,0,-1}); //currentPos,distance,color

        while(queue.size()>0){
            int[] prev = queue.remove();
            List<int[]> nodes = adj[prev[0]];
            for(int[] next:nodes){
                if(!v[next[0]][next[1]] && next[1]!=prev[2]){
                    if(res[next[0]]==-1){
                        res[next[0]]=prev[1] + 1;
                    }
                    v[next[0]][next[1]] = true;
                    queue.add(new int[]{next[0],prev[1]+1,next[1]});
                }
            }
        }
        return res;
    }
}