diff --git a/src/problem/mod.rs b/src/problem/mod.rs
index 4d16cba..125b581 100644
--- a/src/problem/mod.rs
+++ b/src/problem/mod.rs
@@ -116,4 +116,5 @@ mod p392_is_subsequence;
 mod p167_two_sum_ii_input_array_is_sorted;
 mod p209_minimum_size_subarray_sum;
 mod p30_substring_with_concatenation_of_all_words;
-mod p76_minimum_window_substring;
\ No newline at end of file
+mod p76_minimum_window_substring;
+mod p36_valid_sudoku;
\ No newline at end of file
diff --git a/src/problem/p36_valid_sudoku.rs b/src/problem/p36_valid_sudoku.rs
new file mode 100644
index 0000000..4975e48
--- /dev/null
+++ b/src/problem/p36_valid_sudoku.rs
@@ -0,0 +1,77 @@
+/**
+ * [36] Valid Sudoku
+ */
+pub struct Solution {}
+
+// submission codes start here
+use std::collections::HashSet;
+
+impl Solution {
+    pub fn is_valid_sudoku(board: Vec<Vec<char>>) -> bool {
+        let mut set = HashSet::new();
+
+        for i in 0..9 {
+            for j in 0..9 {
+                if board[i][j] == '.' {
+                    continue;
+                }
+
+                if set.contains(&board[i][j]) {
+                    return false;
+                }
+
+                set.insert(board[i][j]);
+            }
+
+            set.clear();
+        }
+
+        for i in 0..9 {
+            for j in 0..9 {
+                if board[j][i] == '.' {
+                    continue;
+                }
+
+                if set.contains(&board[j][i]) {
+                    return false;
+                }
+
+                set.insert(board[j][i]);
+            }
+
+            set.clear();
+        }
+
+        for w in (0..9).step_by(3) {
+            for h in (0..9).step_by(3) {
+                for i in 0..3 {
+                    for j in 0..3 {
+                        if board[w + i][h + j] == '.' {
+                            continue;
+                        }
+
+                        if set.contains(&board[w + i][h + j]) {
+                            return false;
+                        }
+
+                        set.insert(board[w + i][h + j]);
+                    }
+                }
+
+                set.clear();
+            }
+        }
+
+        true
+    }
+}
+
+// submission codes end
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn test_36() {}
+}