問題の説明

せいげんじょうけん

に答える

function solution(n, lost, reserve) {
    let answer = 0;
    let count = 0;
    
    for(let i=0;i<lost.length;i++){
        for(let j=0;j<reserve.length;j++){
            if(lost[i] === reserve[j]){
                lost[i] = '*';
                reserve[j] = '*';
            }
        }
    }
    
    for(let i=0;i<lost.length;i++){
        for(let j=0;j<reserve.length;j++){
            if(lost[i]-1 === reserve[j]||lost[i]+1 === reserve[j]){
                lost[i] = '*';
                reserve[j] = '*';
            }
        }
    }
    
    lost.forEach(item=>{
        if(item !== '*')
            count += 1;
    })
    answer = n - count;
    console.log(answer);
    return answer;
}

チェックポイント