【Q645】随机生成六位数的手机验证码(重复/不可重复)

[shfshanyue]

字节跳动面经一道面试题，见 https://juejin.cn/post/6959364219162607630

相关题目:

• 【Q447】如何实现一个数组洗牌函数 shuffle

[shfshanyue]

const random = n => Math.floor(Math.random() * (n + 1))

// 可生成重复的随机验证码
function randomCode () {
  return [0, 0, 0, 0, 0, 0].map(() => random(9))
}

// 不可生成重复的随机验证码
const shuffle = (list) => list.sort((x, y) => Math.random() - 0.5)
const randomUniqueCode = () => shuffle([0, 1, 2, 3, 4, 5, 6, 7, 8, 9]).slice(0, 6)

// 一种比较低效的解法
function randomUniqueCode2 () {
  let i = 0;
  let l = []
  while (i < 6) {
    const x = random(9)
    if (!l.includes(x)) {
      i++;
      l.push(x)
    }
  }
  return l
}

[real-jacket]

// 不可重复

const numArr = [] 
while(numArr.length < 6){
    let num = parseInt(Math.random()*10)
    if(numArr.indexOf(num) === -1){
        numArr.push(num)
    }
}

[heretic-G]

function sample (length) {
    let arr = Array(100).fill(1).map((_, i) => i / 10 | 0)
    return shuffle(arr, length)
}

function notSample (length) {
    let arr = Array(10).fill(1).map((_, i) => i)
    return shuffle(arr, length)
}

function shuffle (arr, length) {
    let index = 0
    while (index < length) {
        let changeIndex = arr.length - 1 - index
        let randomIndex = Math.round(Math.random() * (changeIndex - 1))
        let temp = arr[changeIndex]
        arr[changeIndex] = arr[randomIndex]
        arr[randomIndex] = temp
        index += 1
    }
    return arr.slice(arr.length - length).join('')
}

[liunengnengneng]

//可重复的 function liunum() { let yanzheng = '' for (let i = 0; i < 6; i++) { let num = Math.floor(Math.random()10) yanzheng += num } return yanzheng } let num = liunum() console.log('重复的',num); //不可重复的 function liunum1() { let yanzheng1 = '' for (let j = 0; j < 6; j++) { let num1 = Math.floor(Math.random()10) if (yanzheng1.indexOf(num1)==-1)yanzheng1 += num1 else j--; } return yanzheng1 } let num1 = liunum1() console.log('不重复的',num1);

[1wkk]

const randTo = (n: number) => ~~(Math.random() * (n + 1))

const shuffle = (list: Array<any>) => list.sort(() => Math.random() - 0.5)

// 随机生成六位数的手机验证码(重复/不可重复)
const vc = ({ len = 6, repeat = true } = {}) => {
  if (len > 10 && repeat === false) {
    throw new Error('len should less equal than 10 if repeat is false')
  }
  if (repeat) {
    return Array(len)
      .fill(0)
      .map(() => randTo(9))
  } else {
    return shuffle([...Array(10).keys()]).slice(0, len)
  }
}

console.log(vc())
console.log(vc({ len: 9 }))
console.log(vc({ repeat: false }))
console.log(vc({ len: 9, repeat: false }))
console.log(vc({ len: 11, repeat: false }))

[createhappymemoryforlife]

const random = (length) => Math.floor(Math.random() * length);

// 重复
const randomCode = () => {
  return [...new Array(6)].map((i) => random(10));
};

// 不重复
const randomUniqueCode = () => {
  let arr = [...new Array(10)].map((_, index) => index);
  return [...new Array(6)].map((i) => {
    const selectIndex = random(arr.length);
    return arr.splice(selectIndex, 1)[0];
  });
};