feat: add two sum solution and tests

cpp/problems/easy/two_sum/two_sum.cpp

@@ -0,0 +1,21 @@
+#include "two_sum.h"
+
+vector<int> twoSum(vector<int> &nums, int target)
+{
+    unordered_map<int, int> map;
+
+    for (size_t i = 0; i < nums.size(); ++i)
+    {
+        int complement = target - nums[i];
+        if (map.find(complement) != map.end())
+        {
+            return {map[complement], static_cast<int>(i)};
+        }
+        else
+        {
+            map[nums[i]] = static_cast<int>(i);
+        }
+    }
+
+    return {};
+}

cpp/problems/easy/two_sum/two_sum.h

@@ -0,0 +1,13 @@
+#ifndef TWO_SUM_H
+#define TWO_SUM_H
+
+#include <vector>
+#include <unordered_map>
+
+using std::unordered_map;
+using std::vector;
+using std::size_t;
+
+vector<int> twoSum(vector<int> &nums, int target);
+
+#endif // TWO_SUM_H

cpp/tests/easy_tests/test_easy.cpp

@@ -1,8 +1,12 @@
 #include "test_easy.h"
 
-#include "add_two_numbers/test_add_two_numbers.h"
+#include "two_sum/test_two_sum.h"
+
+#include <iostream>
 
 void test_easy()
 {
-    test_add_two_numbers();
+    testTwoSum();
+
+    std::cout << "All easy tests passed!" << std::endl;
 }

cpp/tests/easy_tests/two_sum/test_two_sum.cpp

@@ -0,0 +1,35 @@
+#include "test_two_sum.h"
+
+#include <cassert>
+#include <iostream>
+#include "../../../problems/easy/two_sum/two_sum.h"
+
+void test_one()
+{
+    std::vector<int> input = {2, 7, 11, 15};
+    std::vector<int> expected = {0, 1};
+    assert(twoSum(input, 9) == expected);
+}
+
+void test_two()
+{
+    std::vector<int> input = {3, 2, 4};
+    std::vector<int> expected = {1, 2};
+    assert(twoSum(input, 6) == expected);
+}
+
+void test_three()
+{
+    std::vector<int> input = {3, 3};
+    std::vector<int> expected = {0, 1};
+    assert(twoSum(input, 6) == expected);
+}
+
+void testTwoSum()
+{
+    test_one();
+    test_two();
+    test_three();
+
+    std::cout << "All two sum tests passed!" << std::endl;
+}

cpp/tests/easy_tests/two_sum/test_two_sum.h

@@ -0,0 +1,6 @@
+#ifndef TEST_TWO_SUM_H
+#define TEST_TWO_SUM_H
+
+void testTwoSum();
+
+#endif // TEST_TWO_SUM_H

cpp/tests/hard_tests/test_hard.cpp

@@ -2,5 +2,4 @@
 
 void test_hard()
 {
-
 }

cpp/tests/medium_tests/test_medium.cpp

@@ -2,5 +2,4 @@
 
 void test_medium()
 {
-
 }

cpp/tests/test.cpp

@@ -2,9 +2,15 @@
 #include "medium_tests/test_medium.h"
 #include "hard_tests/test_hard.h"
 
-int main() {
+#include <iostream>
+
+int main()
+{
     test_easy();
     test_medium();
     test_hard();
+
+    std::cout << "All tests passed!" << std::endl;
+
     return 0;
 }