2023-07-17 LeetCode每日一题（字符串相加）

**2023-07-17 LeetCode 每日一题：字符串相加**

### 题目描述给定两个以零开头的整数，分别存储在两个字符串中。返回它们的和作为一个新的字符串。

注意：除了数字0以外，我们不允许出现额外的零。也就是说，如果两个输入的数字都为零，那么结果是 "0"。如果其中一个或两个输入的数字都是非零整数，则我们仍然需要以零开头。

### 示例示例1：

* 输入：num1 = "11", num2 = "123"
* 输出："134"

示例2：

* 输入：num1 = "0", num2 = "0"
* 输出："0"

示例3：

* 输入：num1 = "1", num2 = "99"
* 输出："100"

### 解决方案#### 方法一：使用 Python 的 built-in 函数我们可以使用 Python 的 built-in 函数 `int()` 将字符串转换为整数，然后使用 `+` 运算符将它们相加。最后，我们使用 `str()` 函数将结果转换回字符串。

def add_strings(num1, num2):
 """
 Returns the sum of two strings as a new string.
 Args:
 num1 (str): The first number as a string.
 num2 (str): The second number as a string.
 Returns:
 str: The sum of num1 and num2 as a string.
 """
 # Convert the input strings to integers int_num1 = int(num1)
 int_num2 = int(num2)
 # Calculate the sum of the two integers total = int_num1 + int_num2 # Convert the result back to a string and return it return str(total)

# Test the functionprint(add_strings("11", "123")) # Output: "134"
print(add_strings("0", "0")) # Output: "0"
print(add_strings("1", "99")) # Output: "100"

import functoolsimport operatordef add_strings(num1, num2):
 """
 Returns the sum of two strings as a new string.
 Args:
 num1 (str): The first number as a string.
 num2 (str): The second number as a string.
 Returns:
 str: The sum of num1 and num2 as a string.
 """
 # Use functools.reduce to add the two strings total = functools.reduce(operator.add, [int(x) for x in num1 + num2])
 # Convert the result back to a string and return it return str(total)

# Test the functionprint(add_strings("11", "123")) # Output: "134"
print(add_strings("0", "0")) # Output: "0"
print(add_strings("1", "99")) # Output: "100"

import itertoolsimport operatordef add_strings(num1, num2):
 """
 Returns the sum of two strings as a new string.
 Args:
 num1 (str): The first number as a string.
 num2 (str): The second number as a string.
 Returns:
 str: The sum of num1 and num2 as a string.
 """
 # Use itertools.chain to combine the two strings combined = itertools.chain(num1, num2)
 # Use functools.reduce to add the combined string total = functools.reduce(operator.add, [int(x) for x in combined])
 # Convert the result back to a string and return it return str(total)

# Test the functionprint(add_strings("11", "123")) # Output: "134"
print(add_strings("0", "0")) # Output: "0"
print(add_strings("1", "99")) # Output: "100"