EDIST - Edit distance

You are given two strings, A and B. Answer, what is the smallest number of operations you need to
transform A to B?

Operations are:

  1. Delete one letter from one of strings
  2. Insert one letter into one of strings
  3. Replace one of letters from one of strings with another letter


T - number of test cases

For each test case:

  • String A
  • String B

Both strings will contain only uppercase characters and they won't be longer than 2000 characters. 

There will be 10 test cases in data set.


For each test case, one line, minimum number of operations.




hide comments
akki: 2017-04-11 19:59:02

@abbi_18 At any given point you just require only n-elements, hence you don't need to store n*n elements. If you think in this direction you'll be able to reduce space complexity from O(n^2) to O(n).

ashu121: 2017-03-30 20:59:52

AC in one go
use bottom up technique for three operations:
1. insert
2. delete
3. substitute

sunny: 2017-03-19 08:25:52

Nice problem :-). Learned an algorithm.

rishab05: 2017-03-16 03:57:49

It's giving successful results in my IDE and even in ideone. But giving Segmentation fault while submitting.
I am using Memoization approach!!

vijayrit: 2017-03-14 16:22:42

got correct output on ideone but getting segmentation erroe on spoj........
please help

da_201501181: 2017-03-04 11:05:09

Nice Question..!! Learned a lot..!!

programminator: 2017-02-15 12:34:48

I don't understand. Does insertion and deletion take place only at the end or wherever in between?

Fodor Gabor: 2017-01-30 21:09:50

Python (both 2.7 and 3.4) seems to bump into TLE, both for the O(N*2) and O(N) memory versions. There's no point in even trying it. There seems to be 6 successful Python 2.7 submissions from 2015, but maybe they tightened the running time restriction since then.

=(Francky)=> Please use PYPY here ; it will be easier to get AC. Time limit didn't change imho.

Last edit: 2017-01-31 08:05:31
aronzx: 2017-01-23 08:16:08

Top down solution gets TLE??

abbi_18: 2017-01-20 20:21:09

Awesome qs, done it in O(n*n) space complexity, can anybody please suggest a place where i can learn it solve it in O(n) space complexity?

Added by:Mislav Balunović
Time limit:15s
Source limit:50000B
Memory limit:1536MB
Cluster: Cube (Intel G860)