20250516 finished.

src/problem/mod.rs

@@ -656,3 +656,5 @@ mod p3335_total_characters_in_string_after_transformations_i;
 mod p3337_total_characters_in_string_after_transformations_ii;
 
 mod p2900_longest_unequal_adjacent_groups_subsequence_i;
+
+mod p2901_longest_unequal_adjacent_groups_subsequence_ii;

src/problem/p2901_longest_unequal_adjacent_groups_subsequence_ii.rs

@@ -0,0 +1,87 @@
+/**
+ * [2901] Longest Unequal Adjacent Groups Subsequence II
+ */
+pub struct Solution {}
+
+// submission codes start here
+
+impl Solution {
+    pub fn get_words_in_longest_subsequence(words: Vec<String>, groups: Vec<i32>) -> Vec<String> {
+        let n = words.len();
+        let mut dp = vec![1; n];
+        let mut next_pos = vec![None; n];
+
+        for i in 1..n {
+            for j in 0..i {
+                if groups[i] == groups[j] {
+                    continue;
+                }
+
+                if words[i].len() != words[j].len() {
+                    continue;
+                }
+
+                if Self::calculate_hamming_distance(words[i].as_str(), words[j].as_str()) != 1 {
+                    continue;
+                }
+
+                if dp[j] + 1 > dp[i] {
+                    dp[i] = dp[j] + 1;
+                    next_pos[i] = Some(j);
+                }
+            }
+        }
+
+        let max_pos = dp.iter().enumerate().max_by_key(|x| x.1).unwrap();
+        let mut pos = max_pos.0;
+
+        let mut result = vec![words[pos].clone()];
+        while let Some(p) = next_pos[pos] {
+            result.push(words[p].clone());
+            pos = p;
+        }
+
+        result.into_iter().rev().collect()
+    }
+
+    // 计算字符串之间的汉明距
+    // 两个字符串需要等长
+    fn calculate_hamming_distance(a: &str, b: &str) -> usize {
+        a.bytes()
+            .zip(b.bytes())
+            .filter_map(|(x, y)| if x == y { None } else { Some(()) })
+            .count()
+    }
+}
+
+// submission codes end
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn test_2901() {
+        assert_eq!(
+            vec_string!("dc", "dd", "da"),
+            Solution::get_words_in_longest_subsequence(
+                vec_string!("bad", "dc", "bc", "ccd", "dd", "da", "cad", "dba", "aba"),
+                vec![9, 7, 1, 2, 6, 8, 3, 7, 2]
+            )
+        );
+        assert_eq!(
+            vec_string!("bab", "cab"),
+            Solution::get_words_in_longest_subsequence(
+                vec_string!("bab", "dab", "cab"),
+                vec![1, 2, 2]
+            )
+        );
+        assert_eq!(
+            vec_string!("a", "b", "c", "d"),
+            Solution::get_words_in_longest_subsequence(
+                vec_string!("a", "b", "c", "d"),
+                vec![1, 2, 3, 4]
+            )
+        );
+    }
+}