4040
4141<!-- 这里可写通用的实现逻辑 -->
4242
43- 模拟笔算加法的过程，注意进位
43+ ** 方法一：模拟**
44+
45+ 我们用一个变量 $carry$ 记录当前的进位，用两个指针 $i$ 和 $j$ 分别指向 $a$ 和 $b$ 的末尾，从末尾到开头逐位相加即可。
46+
47+ 时间复杂度 $O(\max(m, n))$，其中 $m$ 和 $n$ 分别为字符串 $a$ 和 $b$ 的长度。空间复杂度 $O(1)$。
4448
4549<!-- tabs:start -->
4650
5155``` python
5256class Solution :
5357 def addBinary (self a : str , b : str ) -> str :
54- x, y = len (a) - 1 , len (b) - 1
55- arr = []
56- carry = 0
57- while x >= 0 or y >= 0 :
58- if x >= 0 :
59- if a[x] == ' 1'
60- carry += 1
61- x -= 1
62- if y >= 0 :
63- if b[y] == ' 1'
64- carry += 1
65- y -= 1
66- arr.append(chr ((carry & 1 ) + ord (' 0'
67- carry >>= 1
68- if carry == 1 :
69- arr.append(' 1'
70- return ' ' reversed (arr))
58+ return bin (int (a, 2 ) + int (b, 2 ))[2 :]
59+ ```
60+
61+ ``` python
62+ class Solution :
63+ def addBinary (self a : str , b : str ) -> str :
64+ ans = []
65+ i, j, carry = len (a) - 1 , len (b) - 1 , 0
66+ while i >= 0 or j >= 0 or carry:
67+ carry += (0 if i < 0 else int (a[i])) + (0 if j < 0 else int (b[j]))
68+ carry, v = divmod (carry, 2 )
69+ ans.append(str (v))
70+ i, j = i - 1 , j - 1
71+ return ' ' - 1 ])
7172```
7273
7374### ** Java**
@@ -77,93 +78,103 @@ class Solution:
7778``` java
7879class Solution {
7980 public String addBinary (String a , String b ) {
80- int x = a. length() - 1 , y = b. length() - 1 ;
81- StringBuilder builder = new StringBuilder ();
82- int carry = 0 ;
83- while (x >= 0 || y >= 0 ) {
84- if (x >= 0 ) {
85- if (a. charAt(x) == ' 1'
86- carry += 1 ;
87- }
88- x-- ;
89- }
90- if (y >= 0 ) {
91- if (b. charAt(y) == ' 1'
92- carry += 1 ;
93- }
94- y-- ;
95- }
96- builder. append((char ) ((carry & 1 ) + ' 0'
97- carry >> = 1 ;
81+ var sb = new StringBuilder ();
82+ int i = a. length() - 1 , j = b. length() - 1 ;
83+ for (int carry = 0 ; i >= 0 || j >= 0 || carry > 0 ; -- i, -- j) {
84+ carry += (i >= 0 ? a. charAt(i) - ' 0' : 0 ) + (j >= 0 ? b. charAt(j) - ' 0' : 0 );
85+ sb. append(carry % 2 );
86+ carry /= 2 ;
9887 }
99- if (carry == 1 ) {
100- builder. append(' 1'
101- }
102- return builder. reverse(). toString();
88+ return sb. reverse(). toString();
10389 }
10490}
10591```
10692
93+ ### ** C++**
94+
95+ ``` cpp
96+ class Solution {
97+ public:
98+ string addBinary(string a, string b) {
99+ string ans;
100+ int i = a.size() - 1, j = b.size() - 1;
101+ for (int carry = 0; i >= 0 || j >= 0 || carry; --i, --j) {
102+ carry += (i >= 0 ? a[ i] - '0' : 0) + (j >= 0 ? b[ j] - '0' : 0);
103+ ans.push_back((carry % 2) + '0');
104+ carry /= 2;
105+ }
106+ reverse(ans.begin(), ans.end());
107+ return ans;
108+ }
109+ };
110+ ```
111+
107112### **Go**
108113
109114```go
110115func addBinary(a string, b string) string {
111- x , y := len (a)-1 , len (b)-1
112- var builder strings.Builder
113- carry := 0
114- for x >= 0 || y >= 0 {
115- if x >= 0 {
116- if a[x] == ' 1'
117- carry += 1
118- }
119- x--
116+ i, j := len(a)-1, len(b)-1
117+ ans := []byte{}
118+ for carry := 0; i >= 0 || j >= 0 || carry > 0; i, j = i-1, j-1 {
119+ if i >= 0 {
120+ carry += int(a[i] - '0')
120121 }
121- if y >= 0 {
122- if b[y] == ' 1'
123- carry += 1
124- }
125- y--
122+ if j >= 0 {
123+ carry += int(b[j] - '0')
126124 }
127- builder. WriteRune ( rune (carry& 1 + ' 0'
128- carry >>= 1
125+ ans = append(ans, byte (carry%2+ '0'))
126+ carry /= 2
129127 }
130- if carry == 1 {
131- builder. WriteRune ( ' 1 ' )
128+ for i, j := 0, len(ans)-1; i < j; i, j = i+1, j- 1 {
129+ ans[i], ans[j] = ans[j], ans[i]
132130 }
133- bytes := []byte (builder.String ())
134- for i , j := 0 , len (bytes)-1 ; i < j; i, j = i+1 , j-1 {
135- bytes[i], bytes[j] = bytes[j], bytes[i]
136- }
137- return string (bytes)
131+ return string(ans)
138132}
139133```
140134
141- ### ** C++**
135+ ### ** TypeScript**
136+
137+ ``` ts
138+ function addBinary(a : string , b : string ): string {
139+ let i = a .length - 1 ;
140+ let j = b .length - 1 ;
141+ let ans: number [] = [];
142+ for (let carry = 0 ; i >= 0 || j >= 0 || carry ; -- i , -- j ) {
143+ carry += (i >= 0 ? a [i ] : ' 0' charCodeAt (0 ) - ' 0' charCodeAt (0 );
144+ carry += (j >= 0 ? b [j ] : ' 0' charCodeAt (0 ) - ' 0' charCodeAt (0 );
145+ ans .push (carry % 2 );
146+ carry >>= 1 ;
147+ }
148+ return ans .reverse ().join (' '
149+ }
150+ ```
142151
143- ``` cpp
144- class Solution {
145- public:
146- string addBinary(string a, string b) {
147- string res;
148- int carry = 0;
149-
150- int i = a.size() - 1;
151- int j = b.size() - 1;
152-
153- while (i >= 0 || j >= 0) {
154- int digitA = i >= 0 ? a.at(i--) - '0' : 0;
155- int digitB = j >= 0 ? b.at(j--) - '0' : 0;
156- int sum = digitA + digitB + carry;
157- carry = sum >= 2 ? 1 : 0;
158- sum = sum >= 2 ? sum - 2 : sum;
159- res += to_string(sum);
152+ ### ** Rust**
153+
154+ ``` rust
155+ impl Solution {
156+ pub fn add_binary (a : String , b : String ) -> String {
157+ let mut i = a . len () as i32 - 1 ;
158+ let mut j = b . len () as i32 - 1 ;
159+ let mut carry = 0 ;
160+ let mut ans = String :: new ();
161+ let a = a . as_bytes ();
162+ let b = b . as_bytes ();
163+ while i >= 0 || j >= 0 || carry > 0 {
164+ if i >= 0 {
165+ carry += a [i as usize ] - b '0'
166+ i -= 1 ;
167+ }
168+ if j >= 0 {
169+ carry += b [j as usize ] - b '0'
170+ j -= 1 ;
171+ }
172+ ans . push_str (& (carry % 2 ). to_string ());
173+ carry /= 2 ;
160174 }
161-
162- if (carry == 1 ) res.push_back(' 1'
163- reverse (res.begin(), res.end());
164- return res;
175+ ans . chars (). rev (). collect ()
165176 }
166- };
177+ }
167178```
168179
169180### ** ...**
0 commit comments