936. Stamping The Sequence
LeetCode 936. Stamping The Sequence
Description
You want to form a target
string of lowercase letters.
At the beginning, your sequence is target.length
'?'
marks. You also have a stamp
of lowercase letters.
On each turn, you may place the stamp over the sequence, and replace every letter in the sequence with the corresponding letter from the stamp. You can make up to 10 * target.length
turns.
For example, if the initial sequence is "?????", and your stamp is "abc"
, then you may make "abc??", "?abc?", "??abc" in the first turn. (Note that the stamp must be fully contained in the boundaries of the sequence in order to stamp.)
If the sequence is possible to stamp, then return an array of the index of the left-most letter being stamped at each turn. If the sequence is not possible to stamp, return an empty array.
For example, if the sequence is "ababc", and the stamp is "abc"
, then we could return the answer [0, 2]
, corresponding to the moves "?????" -> "abc??" -> "ababc".
Also, if the sequence is possible to stamp, it is guaranteed it is possible to stamp within 10 * target.length
moves. Any answers specifying more than this number of moves will not be accepted.
Example 1:
Example 2:
Note:
1 <= stamp.length <= target.length <= 1000
stamp
andtarget
only contain lowercase letters.
Tags
String, Greedy
Solution
Extract intact stamps first, then extract the remaining stamps. Reverse the result array as the output.
Complexity
Time complexity: ,
m
for the number of stamps;Space complexity: .
Code
Reference
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