diff --git a/include/s0036_valid_sudoku.hpp b/include/s0036_valid_sudoku.hpp
new file mode 100644
index 0000000..73df99d
--- /dev/null
+++ b/include/s0036_valid_sudoku.hpp
@@ -0,0 +1,15 @@
+#ifndef S0036_VALID_SUDOKU_HPP
+#define S0036_VALID_SUDOKU_HPP
+
+#include <vector>
+#include <unordered_map>
+#include <cmath>
+
+using namespace std;
+
+class Solution {
+ public:
+  bool isValidSudoku(vector<vector<char>>& board);
+};
+
+#endif
diff --git a/src/s0036_valid_sudoku.cpp b/src/s0036_valid_sudoku.cpp
new file mode 100644
index 0000000..4c6855b
--- /dev/null
+++ b/src/s0036_valid_sudoku.cpp
@@ -0,0 +1,38 @@
+#include "s0036_valid_sudoku.hpp"
+
+bool Solution::isValidSudoku(vector<vector<char>>& board) {
+  vector<unordered_map<char, int>> rows;
+  vector<unordered_map<char, int>> columns;
+  vector<unordered_map<char, int>> grids;
+  // Initialize vectors
+  for (int i{0}; i < 9; ++i) {
+    rows.push_back(unordered_map<char, int>{});
+    columns.push_back(unordered_map<char, int>{});
+    grids.push_back(unordered_map<char, int>{});
+  }
+  for (int i{0}; i < 9; ++i) {
+    for (int j{0}; j < 9; ++j) {
+      if (board[i][j] == '.') {
+        continue;
+      }
+      if (rows[j].count(board[i][j]) == 1) {
+        return false;
+      } else {
+        rows[j][board[i][j]] = 1;
+      }
+      if (columns[i].count(board[i][j]) == 1) {
+        return false;
+      } else {
+        columns[i][board[i][j]] = 1;
+      }
+      int gridIndex =
+          static_cast<int>(floor(j / 3)) + 3 * static_cast<int>(floor(i / 3));
+      if (grids[gridIndex].count(board[i][j]) == 1) {
+        return false;
+      } else {
+        grids[gridIndex][board[i][j]] = 1;
+      }
+    }
+  }
+  return true;
+}
diff --git a/tests/s0036_valid_sudoku.cpp b/tests/s0036_valid_sudoku.cpp
new file mode 100644
index 0000000..614afb7
--- /dev/null
+++ b/tests/s0036_valid_sudoku.cpp
@@ -0,0 +1,33 @@
+#include "s0036_valid_sudoku.hpp"
+
+#include <gtest/gtest.h>
+
+TEST(Problem36, Case1) {
+  vector<vector<char>> board{{'5', '3', '.', '.', '7', '.', '.', '.', '.'},
+                             {'6', '.', '.', '1', '9', '5', '.', '.', '.'},
+                             {'.', '9', '8', '.', '.', '.', '.', '6', '.'},
+                             {'8', '.', '.', '.', '6', '.', '.', '.', '3'},
+                             {'4', '.', '.', '8', '.', '3', '.', '.', '1'},
+                             {'7', '.', '.', '.', '2', '.', '.', '.', '6'},
+                             {'.', '6', '.', '.', '.', '.', '2', '8', '.'},
+                             {'.', '.', '.', '4', '1', '9', '.', '.', '5'},
+                             {'.', '.', '.', '.', '8', '.', '.', '7', '9'}};
+  bool o{true};
+  Solution solution;
+  EXPECT_EQ(solution.isValidSudoku(board), o);
+}
+
+TEST(Problem36, Case2) {
+  vector<vector<char>> board{{'8', '3', '.', '.', '7', '.', '.', '.', '.'},
+                             {'6', '.', '.', '1', '9', '5', '.', '.', '.'},
+                             {'.', '9', '8', '.', '.', '.', '.', '6', '.'},
+                             {'8', '.', '.', '.', '6', '.', '.', '.', '3'},
+                             {'4', '.', '.', '8', '.', '3', '.', '.', '1'},
+                             {'7', '.', '.', '.', '2', '.', '.', '.', '6'},
+                             {'.', '6', '.', '.', '.', '.', '2', '8', '.'},
+                             {'.', '.', '.', '4', '1', '9', '.', '.', '5'},
+                             {'.', '.', '.', '.', '8', '.', '.', '7', '9'}};
+  bool o{false};
+  Solution solution;
+  EXPECT_EQ(solution.isValidSudoku(board), o);
+}