Multiply-Strings

题目：Given two non-negative integers num1 and num2 represented as strings, return the product of num1 and num2, also represented as a string.

/**
 * @param {string} num1
 * @param {string} num2
 * @return {string}
 */
var multiply = function(num1, num2) {
  debugger
  let numa = num1.split("")
  let numb = num2.split("")

  let result = []
  let re = []
  if(numa.length === 0 || numb.length === 0) return '0'
  if((numa.length === 1 && numa[0] === '0' )|| (numb.length === 1 && numb[0] === '0')) return '0'
  result.length = (numa.length + numb.length)
  result.fill(0)
  for(let i = numa.length - 1; i >= 0; i--) {
    for(let j = numb.length -1; j >= 0; j--) {
      let sum = numa[i] * numb[j]
      let p1 = i + j
      let p2 = i + j + 1
      sum += result[p2]
      result[p1] += sum / 10 >> 0
      result[p2] = sum % 10
    }
  }
  
  let k = 0
  while(result[k] === 0) k++

  for(let i = k; i < result.length; i++) {
    re.push(result[i])
  }
   return re.join("")
};

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题目连接
参考资料