Merge pull request #128 from FazeelUsmani/add-string

Create 09_addStrings.cpp

Author: abdulbasith007

08 August Leetcode Challenge 2021/09_addStrings.cpp

@@ -0,0 +1,21 @@
+class Solution {
+public:
+    string addStrings(string num1, string num2) {
+        string ans = "";
+        int i1 = num1.size() - 1, i2 = num2.size() - 1, carry = 0;
+        while (i1 >= 0 || i2 >= 0 || carry > 0) {
+            if (i1 >= 0) {
+                carry += num1[i1] - '0';
+                i1 -= 1;
+            }
+            if (i2 >= 0) {
+                carry += num2[i2] - '0';
+                i2 -= 1;
+            }
+            ans += char(carry % 10 + '0');
+            carry /= 10;
+        }
+        reverse(ans.begin(), ans.end());
+        return ans;
+    }
+};