mediumStringsPattern: Mixed
Longest Chained Subsequence Solution
Problem Statement
Given a list of strings `codes`, determine the length of the longest subsequence where each string starts with the last character of the previous string.
Examples
Example 1:
Input:{"codes":["abc","cdf","fgh"]}
Output:3
Explanation: The longest sequence starts with 'abc', ends with 'cdf' or 'fgh', since 'f' in 'cdf' can be followed by 'fgh', but 'a' in 'abc' cannot be followed by 'a' (itself).
Example 2:
Input:{"codes":["a","b","c"]}
Output:1
Explanation: No code starts with the last character of another; hence each forms its own sequence.
Constraints
- 2 <= number of transmission codes <= 100
- 1 <= length of each transmission code <= 10
Time: O(n^2 * m) Space: O(n)
The optimal approach uses dynamic programming to build a graph where each code is a node, and edges connect codes where one code ends with the character another starts, allowing for a much more efficient exploration of possible sequences.
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