2094. Finding 3-Digit Even Numbers

Problem

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You are given an integer array digits, where each element is a digit. The array may contain duplicates.

You need to find all the unique integers that follow the given requirements:

• The integer consists of the concatenation of three elements from digits in any arbitrary order.
• The integer does not have leading zeros.
• The integer is even.

For example, if the given digits were [1, 2, 3], integers 132 and 312 follow the requirements.

Return a sorted array of the unique integers.

Example 1:

Input: digits = [2,1,3,0]
Output: [102,120,130,132,210,230,302,310,312,320]
Explanation: All the possible integers that follow the requirements are in the output array. 
Notice that there are no odd integers or integers with leading zeros.

Example 2:

Input: digits = [2,2,8,8,2]
Output: [222,228,282,288,822,828,882]
Explanation: The same digit can be used as many times as it appears in digits. 
In this example, the digit 8 is used twice each time in 288, 828, and 882. 

Example 3:

Input: digits = [3,7,5]
Output: []
Explanation: No even integers can be formed using the given digits.

Constraints:

• 3 <= digits.length <= 100
• 0 <= digits[i] <= 9

Solution

/**
 * @param {number[]} digits
 * @return {number[]}
 */
  var findEvenNumbers = function(digits) {
    let tmp = [];
    /* 3자리 임시 */
    let tmp2 = [];

    /* 중복제거 */
    let set = new Set();
    /* i와 j를 저장할 변수 */
    let usei,
    usej;

    /* 첫번째는 배열의 크기로 (0제외)*/
  for (let i = 0; i < digits.length; i++) {
    usei = i;
    if (digits[i] == 0) {
      continue;
    }
    for2(usei);
  }

  /* 두번째 */
  function for2(usei2) {
    for (let j = 0; j < digits.length; j++) {
      usej = j;
      if (usei2 == j) {
        continue;
      }
        for3(usei2, usej);
    }
  }

  /* 세번째 */
  function for3(usei3, usej2) {
    for (let v = 0; v < digits.length; v++) {
      if (usei3 == v || usej2 == v) {
        continue;
      }
        tmp2 = [digits[usei3], digits[usej2], digits[v]];
        tmp2 = (parseInt(tmp2.join("")));
        if (tmp2 % 2 == 0) {
          set.add(tmp2);
        }
    }
  }
  let arr = Array.from(set);

  return arr.sort((a, b) => a - b);
};