function solution(n, computers) {
    var answer = n;
    const visited = Array(n).fill(0);
    const checkLinkedComputers = (computer)=>{
        visited[computer] = 1;
        
        for(let j=0; j<n; j++){
            if(visited[j]===1) continue;
            
            const isLinkedComputer = computers[computer][j];
            if(isLinkedComputer){
                visited[j]=1;
                checkLinkedComputers(j);
                answer--;
            }
        }
    }
    
    for(let i=0; i<n; i++){
        checkLinkedComputers(i);
    }
    
    return answer;
}

function solution(n, computers) {    
    const findUnion = () => {
        const visited = [];
        let count = 0;

        const dfs = (vertex, isStart) => {
            if(visited[vertex]){
                return;
            }
            
            visited[vertex] =1;

            computers[vertex].forEach((neighbor, vertex) => neighbor && dfs(vertex, false));
            
            isStart && count++;
        }
        
        for(let i=0; i<computers.length; i++){
            dfs(i, true);
        }
        
        return count;
    }
    
    return findUnion();
}