feat(Codewars): Solve onlinePlatform/codewars/5kyu/square_matrix_multiplication.cc

Author: htbkoo

src/onlinePlatform/codewars/5kyu/CMakeLists.txt

@@ -8,5 +8,14 @@ target_link_libraries(
         rot13GoogleTest
         GTest::gtest_main
 )
-
 gtest_discover_tests(rot13GoogleTest)
+
+add_executable(
+        square_matrix_multiplication_google_test
+        square_matrix_multiplication_google_test.cc
+)
+target_link_libraries(
+        square_matrix_multiplication_google_test
+        GTest::gtest_main
+)
+gtest_discover_tests(square_matrix_multiplication_google_test)

src/onlinePlatform/codewars/5kyu/square_matrix_multiplication.cc

@@ -0,0 +1,23 @@
+// https://www.codewars.com/kata/5263a84ffcadb968b6000513/train/cpp
+
+#include <string>
+#include <vector>
+
+std::vector<std::vector<int>>
+matrix_multiplication(const std::vector<std::vector<int>> &a,
+                      const std::vector<std::vector<int>> &b, size_t n) {
+    // TODO: Return the result of A × B in the form of an n × n matrix
+    // NOTE: Please allocate and return matrix C
+    std::vector<std::vector<int>> c(n, std::vector<int>(n));
+
+    for (int i = 0; i < n; ++i) {
+        for (int j = 0; j < n; ++j) {
+            c[i][j] = 0;
+            for (int k = 0; k < n; ++k) {
+                c[i][j] += a[i][k] * b[k][j];
+            }
+        }
+    }
+
+    return c;
+}

src/onlinePlatform/codewars/5kyu/square_matrix_multiplication_google_test.cc

@@ -0,0 +1,52 @@
+#include <gtest/gtest.h>
+#include <string>
+#include <vector>
+
+#include "square_matrix_multiplication.cc"
+
+void square_matrix_assert_eq(std::vector<std::vector<int>> &actual,
+                             std::vector<std::vector<int>> &expected, int n) {
+  // Assert that the two matrices are equal
+  for (int i = 0; i < n; i++) {
+    for (int j = 0; j < n; j++) {
+      // Assert::That(actual[i][j], Equals(expected[i][j]));
+      EXPECT_EQ(actual[i][j], expected[i][j]);
+    }
+  }
+}
+
+TEST(SquareMatrixMultiplication, should_work_for_the_example_provided_in_the_description) {
+  std::vector<std::vector<int>> a(2, std::vector<int>(2)),
+      b(2, std::vector<int>(2)), expected(2, std::vector<int>(2)), actual;
+  /*
+        1  2
+    A =
+        3  2
+  */
+  // Assuming Row->Col, means storage is row-wise
+  a[0][0] = 1;
+  a[0][1] = 2;
+  a[1][0] = 3;
+  a[1][1] = 2;
+  /*
+        3  2
+    B =
+        1  1
+  */
+  b[0][0] = 3;
+  b[0][1] = 2;
+  b[1][0] = 1;
+  b[1][1] = 1;
+  /*
+              5    4
+    A × B  =
+              11   8
+  */
+  expected[0][0] = 5;
+  expected[0][1] = 4;
+  expected[1][0] = 11;
+  expected[1][1] = 8;
+
+  actual = matrix_multiplication(a, b, 2);
+  square_matrix_assert_eq(actual, expected, 2);
+}