방문 길이

 

const visited = new Set();

const arrowDict = {
  //   x, y
  U: [ 0, 1],
  D: [ 0,-1],
  R: [ 1, 0],
  L: [-1, 0],
}

function token(x, y){
    return String(x)+String(y);
}

function normalize(start, end){
    if(start > end){
        return start+end;
    }
    return end+start;
}

function solution(dirs) {
    let now = [0,0]
    for (const dir of dirs){
        const arrow = arrowDict[dir];
        const nx = now[0] + arrow[0];
        const ny = now[1] + arrow[1];
        if(-5 <= nx && nx <= 5 && -5 <= ny && ny <= 5){
            const start = token(now[0], now[1]);
            const end = token(nx, ny);
            const road = normalize(start, end)
            visited.add(road);
            now = [nx, ny]
        }
    }
    return visited.size;
}