Lv.2 소수 찾기

🤖문제

👍🏻 2022년 2월 2일

<script>
  const permutation = (arr, n) => {
    let result = [];
    if (n === 1) return arr.map((v) => [v]);
    arr.forEach((v, idx, arr) => {
      const fix = v;
      const rest = arr.filter((_, index) => index !== idx);
      const permuationArr = permutation(rest, n - 1);
      const combineFix = permuationArr.map((v) => [fix, ...v]);
      result.push(...combineFix);
    });
    return result;
  }

  const findDecimal = (num) => {
      let cnt = 0;
      if (num === 1) return false;
      else if (num === 2) return true;
      else if (num % 2 === 0) return false;
      else {
          for (let i=0; i<parseInt(num/2); i++) {
              if (num % i === 0) cnt++
              if (cnt === 2) return false;
          }
      }
      return true;
  }


  function solution(numbers) {
      var answer = 0;   
      numbers = numbers.split("");
      let uniquePer = [];
      for (let i=1; i<=numbers.length; i++) {
          let per = permutation(numbers, i);
          per.forEach((v,i) => {
              let num = Number(v.join(""))
              if (uniquePer.indexOf(num) === -1) {
                  uniquePer.push(num);
                  if (findDecimal(num)) {
                      answer++;
                  }
              }
          })
      }
      return answer;
  }
</script>