LeetCode - 67. Add Binary(4ms)
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2022-07-09 12:58:57
Given two binary strings, return their sum (also a binary string). The input strings are both non-empty and contains only characters 1 or 0. Example 1 ......
Given two binary strings, return their sum (also a binary string).
The input strings are both non-empty and contains only characters 1 or 0.
Example 1:
Input: a = "11", b = "1" Output: "100"
Example 2:
Input: a = "1010", b = "1011" Output: "10101"
1 class Solution {
2 public:
3 string addBinary(string a, string b) {
4 int la = a.length();
5 int lb = b.length();
6 string res = "";
7 int car = 0;
8 if(la <= lb) {
9 for(int i = la - 1; i >= 0; i--) {
10 if(a[i] == '1' && b[lb - (la - i)] == '1') {
11 if(car == 1)
12 res = '1' + res;
13 else {
14 res = '0' + res;
15 car = 1;
16 }
17 }
18 else if(a[i] != b[lb - (la - i)]) {
19 if(car == 1)
20 res = '0' + res;
21 else
22 res = '1' + res;
23 }
24 else {
25 if(car == 1) {
26 res = '1' + res;
27 car = 0;
28 }
29 else
30 res = '0' + res;
31 }
32 }
33 for(int i = lb - la - 1; i >= 0; i--) {
34 if(b[i] == '1') {
35 if(car == 1)
36 res = '0' + res;
37 else
38 res = '1' + res;
39 }
40 else {
41 if(car == 1) {
42 res = '1' + res;
43 car = 0;
44 }
45 else
46 res = '0' + res;
47 }
48 }
49 if(car == 1) {
50 res = '1' + res;
51 }
52 return res;
53 }
54 else if(lb < la) {
55 for(int i = lb - 1; i >= 0; i--) {
56 if(b[i] == '1' && a[la - (lb - i)] == '1') {
57 if(car == 1)
58 res = '1' + res;
59 else {
60 res = '0' + res;
61 car = 1;
62 }
63 }
64 else if(b[i] != a[la - (lb - i)]) {
65 if(car == 1)
66 res = '0' + res;
67 else
68 res = '1' + res;
69 }
70 else {
71 if(car == 1) {
72 res = '1' + res;
73 car = 0;
74 }
75 else
76 res = '0' + res;
77 }
78 }
79 for(int i = la - lb - 1; i >= 0; i--) {
80 if(a[i] == '1') {
81 if(car == 1)
82 res = '0' + res;
83 else
84 res = '1' + res;
85 }
86 else {
87 if(car == 1) {
88 res = '1' + res;
89 car = 0;
90 }
91 else
92 res = '0' + res;
93 }
94 }
95 if(car == 1) {
96 res = '1' + res;
97 }
98 return res;
99 }
100 }
101 };