20240819 Finished

src/problem/mod.rs

@@ -209,3 +209,5 @@ mod p221_maximal_square;
 mod p3117_minimum_sum_of_values_by_dividing_array;
 mod p3137_minimum_number_of_operations_to_make_word_k_periodic;
 mod p551_student_attendance_record_i;
+
+mod p552_student_attendance_record_ii;

src/problem/p552_student_attendance_record_ii.rs

@@ -0,0 +1,61 @@
+/**
+ * [552] Student Attendance Record II
+ */
+pub struct Solution {}
+
+
+// submission codes start here
+
+impl Solution {
+    pub fn check_record(n: i32) -> i32 {
+        let mod_number = 1_000_000_007;
+        let n =n as usize;
+        
+        let mut dp = vec![vec![vec![0;3];2];n + 1];
+        dp[0][0][0] = 1;
+        
+        for i in 1..=n {
+            // record ends with 'P'
+            for j in 0..2 {
+                for k in 0..3 {
+                    dp[i][j][0] = (dp[i][j][0] + dp[i - 1][j][k]) % mod_number;
+                }
+            }
+            
+            // record ends with 'A'
+            for k in 0..3 {
+                dp[i][1][0] = (dp[i][1][0] + dp[i - 1][0][k]) % mod_number;
+            }
+            
+            // record ends with 'L'
+            for j in 0..2 {
+                for k in 1..3 {
+                    dp[i][j][k] = (dp[i][j][k] + dp[i - 1][j][k - 1]) % mod_number;
+                }
+            }
+        }
+        
+        let mut result = 0;
+        for i in 0..2 {
+            for j in 0..3 {
+                result = (result + dp[n][i][j]) % mod_number;  
+            }
+        }
+        
+        result
+    }
+}
+
+// submission codes end
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn test_552() {
+        assert_eq!(8, Solution::check_record(2));
+        assert_eq!(3, Solution::check_record(1));
+        assert_eq!(183_236_316, Solution::check_record(10101));
+    }
+}