[LeetCode Sync] Runtime - 5 ms (58.18%), Memory - 18.1 MB (53.58%)

Author: NinePiece2

Solutions/0415-add-strings/README.md

@@ -0,0 +1,34 @@
+<p>Given two non-negative integers, <code>num1</code> and <code>num2</code> represented as string, return <em>the sum of</em> <code>num1</code> <em>and</em> <code>num2</code> <em>as a string</em>.</p>
+
+<p>You must solve the problem without using any built-in library for handling large integers (such as <code>BigInteger</code>). You must also not convert the inputs to integers directly.</p>
+
+<p>&nbsp;</p>
+<p><strong class="example">Example 1:</strong></p>
+
+<pre>
+<strong>Input:</strong> num1 = &quot;11&quot;, num2 = &quot;123&quot;
+<strong>Output:</strong> &quot;134&quot;
+</pre>
+
+<p><strong class="example">Example 2:</strong></p>
+
+<pre>
+<strong>Input:</strong> num1 = &quot;456&quot;, num2 = &quot;77&quot;
+<strong>Output:</strong> &quot;533&quot;
+</pre>
+
+<p><strong class="example">Example 3:</strong></p>
+
+<pre>
+<strong>Input:</strong> num1 = &quot;0&quot;, num2 = &quot;0&quot;
+<strong>Output:</strong> &quot;0&quot;
+</pre>
+
+<p>&nbsp;</p>
+<p><strong>Constraints:</strong></p>
+
+<ul>
+	<li><code>1 &lt;= num1.length, num2.length &lt;= 10<sup>4</sup></code></li>
+	<li><code>num1</code> and <code>num2</code> consist of only digits.</li>
+	<li><code>num1</code> and <code>num2</code> don&#39;t have any leading zeros except for the zero itself.</li>
+</ul>

Solutions/0415-add-strings/solution.py

@@ -0,0 +1,13 @@
+class Solution:
+    def addStrings(self, num1: str, num2: str) -> str:
+        i, j = len(num1) - 1, len(num2) - 1
+        result = []
+        carry = 0
+        while i >= 0 or j >= 0 or carry:
+            val1 = 0 if i < 0 else (ord(num1[i]) - ord("0")) 
+            val2 = 0 if j < 0 else (ord(num2[j]) - ord("0")) 
+            carry, val = divmod(val1 + val2 + carry, 10)
+            result.append(str(val))
+            i, j = i - 1, j - 1
+        return "".join(result[::-1])
+