20240331 Finished

src/problem/mod.rs

@@ -89,4 +89,5 @@ mod p2642_design_graph_with_shortest_path_calculator;
 mod p2580_count_ways_to_group_overlapping_ranges;
 mod p1997_first_day_where_you_have_been_in_all_the_rooms;
 mod p2908_minimum_sum_of_mountain_triplets_i;
-mod p2952_minimum_number_of_coins_to_be_added;
+mod p2952_minimum_number_of_coins_to_be_added;
+mod p331_verify_preorder_serialization_of_a_binary_tree;

src/problem/p331_verify_preorder_serialization_of_a_binary_tree.rs

@@ -0,0 +1,51 @@
+/**
+ * [331] Verify Preorder Serialization of a Binary Tree
+ */
+pub struct Solution {}
+
+
+// submission codes start here
+
+impl Solution {
+    pub fn is_valid_serialization(preorder: String) -> bool {
+        let mut slots = 1;
+        let mut i = preorder.chars();
+
+        while let Some(c) = i.next() {
+            if slots == 0 {
+                return false;
+            }
+
+            if (c == ',') {
+                continue;
+            }
+
+            if (c == '#') {
+                slots -= 1;
+            } else {
+                while let Some(c) = i.next() {
+                    if c == ',' {
+                        break;
+                    }
+                }
+                slots += 1;
+            }
+        }
+
+        slots == 0
+    }
+}
+
+// submission codes end
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn test_331() {
+        assert!(Solution::is_valid_serialization(String::from("9,3,4,#,#,1,#,#,2,#,6,#,#")));
+        assert!(!Solution::is_valid_serialization(String::from("1,#")));
+        assert!(!Solution::is_valid_serialization(String::from("9,#,#,1")));
+    }
+}