Question

A subsequence is anything obtained from a sequence by extracting a subset of elements, but keeping...

A subsequence is anything obtained from a sequence by extracting a subset of elements, but keeping them in the same order; the elements of the subsequence need not be contiguous in the original sequence.

Let A[1 .. m] and B[1 .. n] be two arbitrary arrays. A common subsequence of A and B is another sequence that is a subsequence of both A and B. Describe an efficient algorithm to compute the length of the longest common subsequence of A and B in O(n) time.

Homework Answers

Answer #1

Let the input sequences are A[0..n-1] and B[0..m-1] of lengths m & n respectively. Following is the recursive implementation of the equal subarrays:

Since common subarray of A[] and B[] must start at some index i and j such that A[i] is equals to B[j]. Let dp[i][j] be the longest common subarray of A[i…] and B[j…].
Therefore, for any index i and j, if A[i] is equals to B[j], then dp[i][j] = dp[i+1][j+1] + 1.
The maximum of all the element in the array dp[][] will give the maximum length of equal subarrays.
For Example:
If the given array A[] = {1, 2, 8, 2, 1} and B[] = {8, 2, 1, 4, 7}. If the characters match at index i and j for the array A[] and B[] respectively, then dp[i][j] will be updated as 1 + dp[i+1][j+1].
Below is the updated dp[][] table for the given array A[] and B[].

Know the answer?
Your Answer:

Post as a guest

Your Name:

What's your source?

Earn Coins

Coins can be redeemed for fabulous gifts.

Not the answer you're looking for?
Ask your own homework help question
Similar Questions
1. The failure of the new supply chain system affected Nike adversely. What were the reasons...
1. The failure of the new supply chain system affected Nike adversely. What were the reasons for the failure and how did the breakdown harm Nike? 2. What are the important elements to be kept in mind while implementing a new system in an organization? What is the importance of a good working relationship between partners and the sharing of responsibility in implementing critical projects? What mistakes did Nike and i2 make? 3. comment on the lessons learned and the...
Please answer the following Case analysis questions 1-How is New Balance performing compared to its primary...
Please answer the following Case analysis questions 1-How is New Balance performing compared to its primary rivals? How will the acquisition of Reebok by Adidas impact the structure of the athletic shoe industry? Is this likely to be favorable or unfavorable for New Balance? 2- What issues does New Balance management need to address? 3-What recommendations would you make to New Balance Management? What does New Balance need to do to continue to be successful? Should management continue to invest...
What tools could AA leaders have used to increase their awareness of internal and external issues?...
What tools could AA leaders have used to increase their awareness of internal and external issues? ???ALASKA AIRLINES: NAVIGATING CHANGE In the autumn of 2007, Alaska Airlines executives adjourned at the end of a long and stressful day in the midst of a multi-day strategic planning session. Most headed outside to relax, unwind and enjoy a bonfire on the shore of Semiahmoo Spit, outside the meeting venue in Blaine, a seaport town in northwest Washington state. Meanwhile, several members of...