// https://programmers.co.kr/learn/courses/30/lessons/42840
function solution(answers) {
  const a = [1, 2, 3, 4, 5];
  const b = [2, 1, 2, 3, 2, 4, 2, 5];
  const c = [3, 3, 1, 1, 2, 2, 4, 4, 5, 5];

  let count = [0, 0, 0];
  answers.forEach((element, index) => {
    a[index % a.length] == element ? count[0]++ : null;
    b[index % b.length] == element ? count[1]++ : null;
    c[index % c.length] == element ? count[2]++ : null;
  });
  let result = [];
  let max = Math.max.apply(null, count);
  count.forEach((item, idx) => {
    if (max == item) {
      result.push(idx + 1);
    }
  });
  return result;
}
solution([1, 2, 3, 4, 5]);

// https://programmers.co.kr/learn/courses/30/lessons/42862
function solution(n, lost, reserve) {
  var answer = 0;

  let arr = [];
  for (let i = 0; i < n; i++) {
    arr[i] = 1;
  }

  for (let i = 0; i < reserve.length; i++) {
    arr[reserve[i] - 1]++;
  }

  for (let i = 0; i < lost.length; i++) {
    arr[lost[i] - 1]--;
  }

  for (let i = 0; i < arr.length; i++) {
    // 앞에사람꺼 빌리기
    if (arr[i] == 0) {
      if (arr[i - 1] == 2) {
        arr[i - 1]--;
        arr[i]++;
        continue;
      }
      // 뒤에사람꺼 빌리기
      else if (arr[i + 1] == 2) {
        arr[i + 1]--;
        arr[i]++;
        continue;
      }
    }
  }

  const result = arr.filter((value, index) => {
    return value != 0;
  });

  return result.length;
}
solution(5, [2, 4], [1, 3, 5]);

// https://programmers.co.kr/learn/courses/30/lessons/12901
// 1월:31일
// 2월:29일
// 3월:31일
// 4월:30일
// 5월:31일
// 6월:30일
// 7월:31일
// 8월:31일
// 9월:30일
// 10월:31일
// 11월:30일
// 12월:31일
function solution(a, b) {
  const days = [31, 29, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31];
  const dow = ['SUN', 'MON', 'TUE', 'WED', 'THU', 'FRI', 'SAT'];
  let eachFirstDow = [5];
  let tmp;
  // setup process
  for (let i = 1; i < a; i++) {
    tmp = days[i - 1] % 7;
    console.log(i + 1, dow[(eachFirstDow[i - 1] + tmp) % 7]);
    eachFirstDow[i] = (eachFirstDow[i - 1] + tmp) % 7;
  }
  eachFirstDow.forEach((item) => {
    console.log(dow[item]);
  });
  tmp = (b - 1) % 7;
  return dow[(eachFirstDow[a - 1] + tmp) % 7];
}
result = solution(10, 1);
result = solution(5, 24);

// https://programmers.co.kr/learn/courses/30/lessons/12921
function solution(n) {
  var answer = 0;
  let sosu = [];
  let arr = {};
  for (let i = 2; i <= n; i++) {
    arr[i] = 1;
  }

  for (let index = 2; index <= n; index++) {
    const element = arr[index];
    if (element == 0) {
      console.log('index', index);
      continue;
    }
    sosu.push(index);
    let a = 2;
    // 지금 현재 값을
    while (true) {
      if (!(arr[index * a] + 1)) {
        break;
      }
      arr[index * a++] = 0;
      console.log(index * a);
    }
  }
  console.log('소수:', sosu);
  return sosu.length;
}
result = solution(10);

// https://programmers.co.kr/learn/courses/30/lessons/12928
function solution(n) {
  if (n == 0 || n == 1) {
    return n;

  let arr = [1, n];
  console.log(Math.sqrt(n));
  for (let index = 2; index <= Math.sqrt(n); index++) {
    if (n % index == 0) {
      arr.push(index);
      if (index == Math.sqrt(n)) {
      } else {
        arr.push(n / index);
      }
    }
  }
  console.log(arr);
  return arr.reduce((prev, curr) => {
    console.log(prev, curr);
    return curr + prev;
  }, 0);
}
result = solution(12); //28

// https://programmers.co.kr/learn/courses/30/lessons/12931
function solution(n) {
  let answer;
  n = `${n}`;
  n = n.split('');
  answer = n.reduce((prev, curr) => {
    return parseInt(curr) + parseInt(prev);
  }, 0);
  return answer;
}
result = solution(123);

// https://programmers.co.kr/learn/courses/30/lessons/12932
function solution(n) {
  var answer = [];
  answer = `${n}`.split('').map(Number);
  answer.reverse();
  return answer;
}
result = solution(12345);

// https://programmers.co.kr/learn/courses/30/lessons/12933
function solution(n) {
  n = n + '';
  let arr = n.split('');
  arr.sort((a, b) => b - a);
  arr = arr.join('');
  return Number(arr);
}
result = solution(118372);

// https://programmers.co.kr/learn/courses/30/lessons/12934
function solution(n) {
  let answer = -1;
  const x = Math.sqrt(n);
  if (Number.isInteger(x)) {
    answer = Math.pow(x + 1, 2);
  }
  return answer;
}
result = solution(121);

//  https://programmers.co.kr/learn/courses/30/lessons/12935
function solution(arr) {
  var answer = [-1];
  // 하나일때 바로 반환
  if (arr.length == 1) {
    return answer;
  }
  let min = Math.min.apply(null, arr);
  // let min = Math.min(...arr);
  let tmp = arr.filter((val, idx) => {
    return val != min;
  });
  console.log(tmp);
  return tmp;
}

result = solution([4, 3, 2, 1]);

function solution2(arr) {
  arr.splice(arr.indexOf(Math.min(...arr)), 1);
  if (arr.length < 1) return [-1];
  return arr;
}
result = solution([4, 3, 2, 1]);