Strobogrammatic Number II

Description

null

Solution(javascript)

/**
 * @param {number} n
 * @return {string[]}
 */
const findStrobogrammatic = function (n) {
  const map = {
    6: '9',
    9: '6',
    1: '1',
    0: '0',
    8: '8',
  }
  const result = []
  const candidates = ['9', '6', '1', '0', '8']
  const aux = (remain, left, right) => {
    // 注意 "00" 不对， "00"就是 "0"
    if (left[0] === '0') {
      return
    }

    if (remain === 0) {
      result.push(left + right)
      return
    }
    if (remain === 1) {
      result.push(
        `${left}1${right}`,
        `${left}0${right}`,
        `${left}8${right}`,
      )
      return
    }
    for (let i = 0; i < candidates.length; i++) {
      aux(remain - 2, left + candidates[i], map[candidates[i]] + right)
    }
  }
  aux(n, '', '')
  return result
}