commit solution 415

Author: lxlxw

solution/400-499/0415.add-strings/README.md

@@ -0,0 +1,43 @@
+# [415. 字符串相加](https://leetcode-cn.com/problems/add-strings/description/)
+
+
+### 题目描述
+
+<p>给定两个字符串形式的非负整数&nbsp;<code>num1</code> 和<code>num2</code>&nbsp;，计算它们的和。</p>
+
+<p><strong>注意：</strong></p>
+
+<ol>
+	<li><code>num1</code> 和<code>num2</code>&nbsp;的长度都小于 5100.</li>
+	<li><code>num1</code> 和<code>num2</code> 都只包含数字&nbsp;<code>0-9</code>.</li>
+	<li><code>num1</code> 和<code>num2</code> 都不包含任何前导零。</li>
+	<li><strong>你不能使用任何內建 BigInteger 库，&nbsp;也不能直接将输入的字符串转换为整数形式。</strong></li>
+</ol>
+
+### 解题思路
+
+
+### 代码实现
+
+
+#### **Golang**
+```go
+func addStrings(num1 string, num2 string) string {
+    add := 0
+    ans := ""
+    for i, j := len(num1) - 1, len(num2) - 1; i >= 0 || j >= 0 || add != 0; i, j = i - 1, j - 1 {
+        var x, y int
+        if i >= 0 {
+            x = int(num1[i] - '0')
+        }
+        if j >= 0 {
+            y = int(num2[j] - '0')
+        }
+        result := x + y + add
+        ans = strconv.Itoa(result%10) + ans
+        add = result / 10
+    }
+    return ans
+}
+```
+

solution/400-499/0415.add-strings/solution.go

@@ -0,0 +1,26 @@
+/*
+ * @lc app=leetcode.cn id=415 lang=golang
+ *
+ * [415] 字符串相加
+ */
+
+// @lc code=start
+func addStrings(num1 string, num2 string) string {
+    add := 0
+    ans := ""
+    for i, j := len(num1) - 1, len(num2) - 1; i >= 0 || j >= 0 || add != 0; i, j = i - 1, j - 1 {
+        var x, y int
+        if i >= 0 {
+            x = int(num1[i] - '0')
+        }
+        if j >= 0 {
+            y = int(num2[j] - '0')
+        }
+        result := x + y + add
+        ans = strconv.Itoa(result%10) + ans
+        add = result / 10
+    }
+    return ans
+}
+// @lc code=end
+