2020-07-25 BD真题 大数相加

let x = "389238948299";
let y = "99999999";

let xlen = x.length;
let ylen = y.length;

let len = xlen>ylen ? xlen : ylen;

let res = [];
let ten = 0;

for(let i=0; i<len; i++) {
    if(i<xlen) {
    x1 = x[xlen-i-1]
  } else {
    x1 = 0;
  }
  if(i<ylen) {
    y1 = y[ylen-i-1];
  } else {
    y1 = 0;
  }
  let sum = Number(x1) +Number(y1) + ten;
  if(sum>=10) {
    ten = 1;
    res.unshift(sum-10);
  } else {
    ten = 0;
    res.unshift(sum);
  }
}
if(ten) res.unshift(ten);

console.log(res.join``)