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File summary

• Purpose: Computes and prints the Longest Common Subsequence (LCS) of two input strings and its length using dynamic programming and backpointers.
• Language: Java
• Entry point: public class Lcs with main method reading two tokens from stdin.

How it works (brief)

• Builds an (m+1) x (n+1) table of cells that store:
  • v: length of LCS for prefixes up to that cell
  • d: direction/backpointer ('d' = diagonal / match, 'u' = up, 's' = left)
• Fills the table row by row: when characters match, take diagonal+1; otherwise take the larger of up or left and record direction.
• Recursively follows backpointers from cost[m][n] to print the LCS in the correct order.
• Finally prints the LCS and its length.

Known issues / bugs to fix

• The source defines class C but uses D[][] cost and new D() — mismatch (compile error). Fix by renaming C to D or change D to C.
• Minor typos in output text ("LENGHT" → "LENGTH").
• Scanner.next() reads a token (no spaces). If you want full lines use Scanner.nextLine().
• Direction character 's' is used for left; consider using 'l' for clarity.
• Class and method naming: consider following Java conventions (class names start with uppercase, methods camelCase).
• Current implementation stores the whole table (O(m*n) memory). If you only need the length, memory can be reduced to O(min(m,n)).

Time & space complexity

• Time: O(m * n) where m = length of string a, n = length of string b.
• Space: O(m * n) for the full DP table and backpointers. Can be reduced to O(min(m,n)) if only the length is required (but not the sequence reconstruction).

Usage / example

• Compile: javac Lcs.java
• Run: java Lcs
• Example interactive run:
  • Input: ENTER STRING 1: AGGTAB ENTER STRING 2: GXTXAYB
  • Output: LONGEST COMMON SUBSEQUENCE IS: GTAB LENGHT OF THE LCS IS: 4

Suggested small corrections (summary)

• Rename class C → D (or change all D references to C).
• Fix printed messages spelling.
• Consider handling full lines with nextLine() if inputs may contain spaces.
• Optionally change direction markers to clearer names and add comments.
• Add unit tests or example runs in a README.

If you want, I can:

• Provide a corrected version of the file (compilable).
• Produce detailed inline comments or a README.md content for the repo. Which would you prefer?