2021-05.md

字节2面

// implement a function to calculate a formula string with 'plus' and 'minus'
// no need to worry about big number problem


console.log(calc(test)) // 11
var test = '-1+31-1-1-1-24+100-92' // 13
function rev(num) { return ~~Array.from(num).reverse().join('') }
function calc(str) {
    let cur = ''
    let arr = []
    for(let i = str.length - 1 ; i >= 0; i --) {
        let c = str[i];
        if(!isNaN(Number(c))) {
            cur += c
        } else {
            arr.push(c === '+' ? rev(cur) : -1 * rev(cur))
            cur = ''
        }
    }
    return arr.reduce((a, b) => a + b)
}

console.log(calc(test))

八股

async function async1() {
  console.log('async1 start');
  await async2();
  console.log('async1 end');
}

async function async2() {
  console.log('async2');
}

console.log('script start');

setTimeout(function() {
    console.log('setTimeout');
}, 0);  

async1();

new Promise(function(resolve) {
    console.log('promise1');
    resolve();
  }).then(function() {
    console.log('promise2');
});

console.log('script end');


// answer


// 'script start'
// 'async1 start'
// 'async2'
// 'promise1'
// 'script end'
// 'async1 end'
// 'prpmise2'
// 'setTimeout''script start'
// 'async1 start'
// 'async2'
// 'promise1'
// 'script end'
// 'async1 end'
// 'prpmise2'
// 'setTimeout'

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0507 字节三面 微信红包的随机算法 给金额和人数，返回红包金额