Stamping The Sequence
hard · verified · 62.2% accepted · 1,578 likes · top 63%
string · stack · greedy · queue
Description
You are given two strings stamp and target. Initially, there is a string s of length target.length with all s[i] == '?'.
In one turn, you can place stamp over s and replace every letter in the s with the corresponding letter from stamp.
- For example, if stamp = "abc" and target = "abcba", then s is "?????" initially. In one turn you can:
- place stamp at index 0 of s to obtain "abc??",
- place stamp at index 1 of s to obtain "?abc?", or
- place stamp at index 2 of s to obtain "??abc".
Note that stamp must be fully contained in the boundaries of s in order to stamp (i.e., you cannot place stamp at index 3 of s).
We want to convert s to target using at most 10 * target.length turns.
Return an array of the index of the left-most letter being stamped at each turn. If we cannot obtain target from s within 10 * target.length turns, return an empty array.
Example 1:
Example 2:
Solution