없는-숫자-더하기&86051&.js

//https://github.com/codeisneverodd/programmers-coding-test
//더 좋은 풀이가 존재할 수 있습니다.
//정답 1(🎩 refactor 220425) - codeisneverodd
function solution(numbers) {
  return 45 - numbers.reduce((a, b) => a + b);
}

//정답 2 - codeisneverodd
function solution(numbers) {
  var answer = 0;
  for (let i = 0; i < 10; i++) {
    answer += numbers.includes(i) ? 0 : i;
  }
  return answer;
}

//정답 3 - yongchanson
function solution(numbers) {
  var answer = -1;

  let arr = [0, 1, 2, 3, 4, 5, 6, 7, 8, 9];
  let arr_sum = 0;
  let numbers_sum = 0;

  for (i = 0; i < arr.length / 2; i++) {
    if (arr[i] == arr[arr.length - 1 - i]) {
      arr_sum += arr[i];
    } else {
      arr_sum += arr[i] + arr[arr.length - 1 - i];
    }
  }

  for (i = 0; i < numbers.length; i++) {
    numbers_sum += numbers[i];
  }

  answer = arr_sum - numbers_sum;
  return answer;
}

//정답 4 - prove-ability
function solution(numbers) {
  var answer = 0;

  for (let i = 0; i < 10; i++) {
    if (!numbers.includes(i)) answer += i;
  }

  return answer;
}

//정답 5 - chaerin-dev
function solution(numbers) {
  let answer = 0;
  for (let i = 0; i <= 9; i++) {
    if (!numbers.includes(i)) answer += i;
  }
  return answer;
}