1576. Replace All ?'s to Avoid Consecutive Repeating Characters: AC

Author: tan-wei

src/solution/mod.rs

@@ -1188,3 +1188,4 @@ mod s1572_matrix_diagonal_sum;
 mod s1573_number_of_ways_to_split_a_string;
 mod s1574_shortest_subarray_to_be_removed_to_make_array_sorted;
 mod s1575_count_all_possible_routes;
+mod s1576_replace_all_s_to_avoid_consecutive_repeating_characters;

src/solution/s1576_replace_all_s_to_avoid_consecutive_repeating_characters.rs

@@ -0,0 +1,72 @@
+/**
+ * [1576] Replace All ?'s to Avoid Consecutive Repeating Characters
+ *
+ * Given a string s containing only lowercase English letters and the '?' character, convert all the '?' characters into lowercase letters such that the final string does not contain any consecutive repeating characters. You cannot modify the non '?' characters.
+ * It is guaranteed that there are no consecutive repeating characters in the given string except for '?'.
+ * Return the final string after all the conversions (possibly zero) have been made. If there is more than one solution, return any of them. It can be shown that an answer is always possible with the given constraints.
+ *  
+ * Example 1:
+ *
+ * Input: s = "?zs"
+ * Output: "azs"
+ * Explanation: There are 25 solutions for this problem. From "azs" to "yzs", all are valid. Only "z" is an invalid modification as the string will consist of consecutive repeating characters in "zzs".
+ *
+ * Example 2:
+ *
+ * Input: s = "ubv?w"
+ * Output: "ubvaw"
+ * Explanation: There are 24 solutions for this problem. Only "v" and "w" are invalid modifications as the strings will consist of consecutive repeating characters in "ubvvw" and "ubvww".
+ *
+ *  
+ * Constraints:
+ *
+ * 	1 <= s.length <= 100
+ * 	s consist of lowercase English letters and '?'.
+ *
+ */
+pub struct Solution {}
+
+// problem: https://leetcode.com/problems/replace-all-s-to-avoid-consecutive-repeating-characters/
+// discuss: https://leetcode.com/problems/replace-all-s-to-avoid-consecutive-repeating-characters/discuss/?currentPage=1&orderBy=most_votes&query=
+
+// submission codes start here
+
+impl Solution {
+    pub fn modify_string(s: String) -> String {
+        let mut result = String::with_capacity(s.len());
+        let mut peekable = s.chars().peekable();
+
+        while let Some(curr) = peekable.next() {
+            if curr != '?' {
+                result.push(curr);
+                continue;
+            }
+
+            result.push(
+                match (
+                    result.chars().last().unwrap_or('c'),
+                    *peekable.peek().unwrap_or(&'c'),
+                ) {
+                    ('a', 'a') => 'b',
+                    ('b', 'b') => 'a',
+                    ('a', 'b') | ('b', 'a') => 'c',
+                    ('a', _) | (_, 'a') => 'b',
+                    ('b', _) | (_, 'b') => 'a',
+                    (_, _) => 'a',
+                },
+            )
+        }
+
+        result
+    }
+}
+
+// submission codes end
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn test_1576_example_1() {}
+}