二进制求和
- 难度: 简单
- 通过率: 37.1%
- 题目链接:https://leetcode-cn.com/problems/add-binary
题目描述
给定两个二进制字符串,返回他们的和(用二进制表示)。
输入为非空字符串且只包含数字 1
和 0
。
示例 1:
输入: a = "11", b = "1" 输出: "100"
示例 2:
输入: a = "1010", b = "1011" 输出: "10101"
解法:
逐项相加向前进位即可。
class Solution:
def addBinary(self, a, b):
"""
:type a: str
:type b: str
:rtype: str
"""
cy = 0
bits = []
i = len(a) - 1
j = len(b) - 1
while i >= 0 or j >= 0:
if i < 0:
bit_a = 0
else:
bit_a = int(a[i])
if j < 0:
bit_b = 0
else:
bit_b = int(b[j])
i -= 1
j -= 1
bit_sum = (bit_a + bit_b + cy)
cy = bit_sum // 2
bits.append(bit_sum % 2)
if cy:
bits.append(cy)
return ''.join(map(str, bits[::-1]))