feat: Add solution for LeetCode #67

Author: 0xMashiro

SOLVED.md

@@ -12,6 +12,7 @@
 | 62 | [Unique Paths](https://leetcode.com/problems/unique-paths/) | [Code](src/leetcode/problems/unique-paths.cpp) / [Test](test/leetcode/problems/unique-paths.cpp) |
 | 63 | [Unique Paths II](https://leetcode.com/problems/unique-paths-ii/) | [Code](src/leetcode/problems/unique-paths-ii.cpp) / [Test](test/leetcode/problems/unique-paths-ii.cpp) |
 | 66 | [Plus One](https://leetcode.com/problems/plus-one/) | [Code](src/leetcode/problems/plus-one.cpp) / [Test](test/leetcode/problems/plus-one.cpp) |
+| 67 | [Add Binary](https://leetcode.com/problems/add-binary/) | [Code](src/leetcode/problems/add-binary.cpp) / [Test](test/leetcode/problems/add-binary.cpp) |
 | 68 | [Text Justification](https://leetcode.com/problems/text-justification/) | [Code](src/leetcode/problems/text-justification.cpp) / [Test](test/leetcode/problems/text-justification.cpp) |
 | 71 | [Simplify Path](https://leetcode.com/problems/simplify-path/) | [Code](src/leetcode/problems/simplify-path.cpp) / [Test](test/leetcode/problems/simplify-path.cpp) |
 | 85 | [Maximal Rectangle](https://leetcode.com/problems/maximal-rectangle/) | [Code](src/leetcode/problems/maximal-rectangle.cpp) / [Test](test/leetcode/problems/maximal-rectangle.cpp) |

include/leetcode/problems/add-binary.h

@@ -0,0 +1,18 @@
+#include "leetcode/core.h"
+
+namespace leetcode {
+namespace problem_67 {
+
+using Func = std::function<string(string, string)>;
+
+class AddBinarySolution : public SolutionBase<Func> {
+ public:
+  //! 67. Add Binary
+  //! https://leetcode.com/problems/add-binary/
+  string addBinary(string a, string b);
+
+  AddBinarySolution();
+};
+
+}  // namespace problem_67
+}  // namespace leetcode

src/leetcode/problems/add-binary.cpp

@@ -0,0 +1,47 @@
+#include "leetcode/problems/add-binary.h"
+
+namespace leetcode {
+namespace problem_67 {
+
+// 模拟二进制加法
+// 从字符串末尾开始逐位相加，处理进位
+// 时间复杂度: O(max(n, m)), 空间复杂度: O(max(n, m))
+static string solution1(string a, string b) {
+  string result;
+  int i = a.size() - 1;
+  int j = b.size() - 1;
+  int carry = 0;
+  
+  // 从低位到高位逐位相加
+  while (i >= 0 || j >= 0 || carry > 0) {
+    int sum = carry;
+    if (i >= 0) {
+      sum += a[i] - '0';
+      i--;
+    }
+    if (j >= 0) {
+      sum += b[j] - '0';
+      j--;
+    }
+    result.push_back((sum % 2) + '0');
+    carry = sum / 2;
+  }
+  
+  // 反转结果（因为我们是从低位到高位计算的）
+  reverse(result.begin(), result.end());
+  return result;
+}
+
+AddBinarySolution::AddBinarySolution() {
+  setMetaInfo({.id = 67,
+               .title = "Add Binary",
+               .url = "https://leetcode.com/problems/add-binary/"});
+  registerStrategy("Simulation", solution1);
+}
+
+string AddBinarySolution::addBinary(string a, string b) {
+  return getSolution()(a, b);
+}
+
+}  // namespace problem_67
+}  // namespace leetcode

test/leetcode/problems/add-binary.cpp

@@ -0,0 +1,55 @@
+#include "leetcode/problems/add-binary.h"
+
+#include "gtest/gtest.h"
+
+namespace leetcode {
+namespace problem_67 {
+
+class AddBinaryTest : public ::testing::TestWithParam<string> {
+ protected:
+  void SetUp() override { solution.setStrategy(GetParam()); }
+
+  AddBinarySolution solution;
+};
+
+TEST_P(AddBinaryTest, Example1) {
+  string a = "11";
+  string b = "1";
+  string expected = "100";
+  EXPECT_EQ(expected, solution.addBinary(a, b));
+}
+
+TEST_P(AddBinaryTest, Example2) {
+  string a = "1010";
+  string b = "1011";
+  string expected = "10101";
+  EXPECT_EQ(expected, solution.addBinary(a, b));
+}
+
+TEST_P(AddBinaryTest, SimpleCase) {
+  string a = "0";
+  string b = "0";
+  string expected = "0";
+  EXPECT_EQ(expected, solution.addBinary(a, b));
+}
+
+TEST_P(AddBinaryTest, DifferentLength) {
+  string a = "1";
+  string b = "111";
+  string expected = "1000";
+  EXPECT_EQ(expected, solution.addBinary(a, b));
+}
+
+TEST_P(AddBinaryTest, CarryPropagation) {
+  string a = "111";
+  string b = "111";
+  string expected = "1110";
+  EXPECT_EQ(expected, solution.addBinary(a, b));
+}
+
+INSTANTIATE_TEST_SUITE_P(
+    LeetCode, AddBinaryTest,
+    ::testing::ValuesIn(AddBinarySolution().getStrategyNames()));
+
+}  // namespace problem_67
+}  // namespace leetcode