Leetcode 43 Multiply Strings

class Solution:
# @param {string} num1
# @param {string} num2
# @return {string}
def multiply(self, num1, num2):
if num1 == "0" or num2 == "0": return "0"

result = [0] * (len(num1) + len(num2))
num1 = [int(i) for i in num1]
num2 = [int(i) for i in num2]

for index1 in xrange(len(num1)):
multiplier = num1[index1]
temp = [i*multiplier for i in num2] # Multiply
temp.extend([0] * (len(num1) - index1 - 1)) # Shift

for resIndex in xrange(1, len(temp) + 1):
result[-resIndex] += temp[-resIndex]

for resIndex in xrange(len(result)-1, 0, -1):
result[resIndex-1] += result[resIndex] // 10
result[resIndex] %= 10

result = "".join([str(i) for i in result]).lstrip("0")
return result

class Solution:
# @param num1, a string
# @param num2, a string
# @return a string
def multiply(self, num1, num2):
num1 = num1[::-1]; num2 = num2[::-1]
arr = [0 for i in range(len(num1)+len(num2))]
for i in range(len(num1)):
for j in range(len(num2)):
arr[i+j] += int(num1[i]) * int(num2[j])
ans = []
for i in range(len(arr)):
digit = arr[i] % 10
carry = arr[i] / 10
if i < len(arr)-1:
arr[i+1] += carry
ans.insert(0, str(digit))
while ans[0] == '0' and len(ans) > 1:
del ans[0]
return ''.join(ans)