Sum Strings as Numbers

[Jerry Liang]

Sum Strings as Numbers

Given the string representations of two integers, return the string representation of the sum of those integers.

For example:

sumStrings('1','2') // => '3'

A string representation of an integer will contain no characters besides the ten numerals "0" to "9".

replay

function sumStrings(a,b) { 
  // 设置var，记录进位，设置连续0的标识位
  let [result,empty,zero] = [[],0,0];
  // 获取最大的字符串长度
  let max = Math.max(a.length,b.length);
  for(let i=0;i<max;i++){
    let A = a.length - i - 1<0 ? 0 : Number(a[a.length - i - 1]);
    let B = b.length - i - 1<0 ? 0 : Number(b[b.length - i - 1]);
    let r = A + B + empty;
    zero = r == 0?max-i:0;
    if(i == max-1){
      result.unshift(r);
    } else {
      if(r<10){
        empty = 0;
        result.unshift(r);
      } else {
        empty = 1;
        result.unshift(r-10);
      }
    }
  }
  return result.join('').substring(zero);
}