44. 547. Number of Provinces

class Solution {
    boolean isVisited[];
    public int findCircleNum(int[][] isConnected) {
        //total no of rooms
        int totalRooms = isConnected.length;
        isVisited = new boolean[totalRooms];

        //count different no of group
        int cnt=0;

        //visit room one by one and check and count
        for(int i=0;i<totalRooms;i++){
            //if room is not visited then increase count by 1 and visit the room using dfs method
            if(!isVisited[i]){
                cnt++;
                dfs(i,totalRooms,isConnected);
            }
        }

        //this will return total no of group 
        return cnt;
        
    }

    private void dfs(int currentRoom,int totalRooms,int [][]isConnected){
        isVisited[currentRoom]=true;
        //now we find ount connected room of current room 
        List<Integer> adjRooms = new ArrayList<Integer>();
        for(int i=0;i<isConnected[currentRoom].length;i++){
            if(isConnected[currentRoom][i]==1){
                adjRooms.add(i);
            }
        }

        //now we visit every room which is connected to current room , 
        //so we make group of room which is connected to current room
        for(int room:adjRooms){
            //if room is not visited then we visit 
            if(!isVisited[room]){
                dfs(room,totalRooms,isConnected);
            }
        }
    }
}