[프로그래머스] 완주하지 못한 선수 (JavaScript)

link 🔗 https://school.programmers.co.kr/learn/courses/30/lessons/42576?language=javascript 

프로그래머스

 

📌 효율성 테스트 통과 못한 코드

function solution(participant, completion) {
    var answer = "";
    participant.map((word)=>{
        if(completion.includes(word)){
            let where = completion.indexOf(word)
            completion.splice(where, 1)
        }else{
            answer = word;
        }
    });
    
    return answer;
}

 

📌 효율성까지 통과한 코드

function solution(participant, completion) {
    var answer = "";
    let isComple = {};
    participant.map((word)=>{
        if(word in isComple){
            isComple[word] += 1
        }else{
            isComple[word] = 1
        }
    })
    completion.map((word)=>{
        isComple[word] -= 1
    })
    let keys = Object.keys(isComple)
    keys.map((word)=>{
        if(isComple[word] === 1){
            answer = word;
        }
    })
    return answer;
}