Add 2 strings of big numbers
Similar Problems:
Given two non-negative integers num1 and num2 represented as string, return the sum of num1 and num2.
Note:
- The length of both num1 and num2 is < 5100.
- Both num1 and num2 contains only digits 0-9.
- Both num1 and num2 does not contain any leading zero.
- You must not use any built-in BigInteger library or convert the inputs to integer directly.
Github: code.dennyzhang.com
Credits To: leetcode.com
Leave me comments, if you have better ways to solve.
// Blog link: https://code.dennyzhang.com/add-strings // Basic Ideas: // Handle carry // Only stop when both strings have finished // Complexity: Time O(n), Space O(n) import "strconv" func addStrings(num1 string, num2 string) string { carry, res := 0, "" for i, j:= len(num1)-1, len(num2)-1; i>=0 || j>=0 || carry!=0; i, j = i-1, j-1 { v1, v2, v := 0, 0, 0 if i>=0 { v1, _ = strconv.Atoi(string(num1[i])) } if j>=0 { v2, _ = strconv.Atoi(string(num2[j])) } v = v1+v2+carry if v>=10 { carry = 1 v -= 10 } else { carry = 0 } res = strconv.Itoa(v)+res } return res }
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