프로그래머스 | 섬 연결하기

function solution(n, costs) {
    var answer = 0;
    let visited=new Array(n).fill(false);
    let builded=new Array(costs.length).fill(false);
    costs.sort((a,b)=>a[2]-b[2]);
    visited[costs[0][0]]=true;
    visited[costs[0][1]]=true;
    builded[0]=true;
    answer+=costs[0][2];
    let num=1;
    while(n-1>num){
        for(let i=1;i<costs.length;i++){
            let [pointA, pointB, cost]=costs[i];
            if(!builded[i]&&(
                (visited[pointA]&&!visited[pointB])||
                (!visited[pointA]&&visited[pointB]))){
                answer+=cost;
                visited[pointA]=true;
                visited[pointB]=true;
                builded[i]=true;
                num++;
                break;
            }
        }
    }

    return answer;
}

Find-Union 알고리즘 사용

function solution(n, costs) {
    var answer = 0;
    let table=new Array(n).fill(0).map((e,idx)=>idx);
    costs.sort((a,b)=>a[2]-b[2]);
 
    const isAllSame=(table)=>{
        for(let i=1;i<table.length;i++){
            if(table[i]!==table[i-1])return false;
        }
        return true;
    };
    
    const changeTable=(start,end,table)=>{
        let tableEnd=table[end];
        let tableStart=table[start];
        for(let i=0;i<table.length;i++){
            if(table[i]===tableEnd){
                table[i]=tableStart;
            }
        }
        return table;
    };
    
    while(!isAllSame(table)){
        let [start,end,cost]=costs.shift();
        if(table[start]!==table[end]){
            table=changeTable(start,end, table);
            answer+=cost;
        }
    }
    return answer;
}