Design a search autocomplete system for a search engine. Users may input a sentence (at least
one word and end with a special character '#'
). For each
character they type except '#', you need to return the top 3
historical hot sentences that have prefix the same as the part of sentence already typed.
Here are the specific rules:
Your job is to implement the following functions:
The constructor function:
AutocompleteSystem(String[] sentences, int[] times):
This is the constructor.
The input is historical data. Sentences
is a string array consists of
previously typed sentences. Times
is the corresponding times a sentence has
been typed. Your system should record these historical data.
Now, the user wants to input a new sentence. The following function will provide the next character the user types:
List<String> input(char c):
The input c
is the next character
typed by the user. The character will only be lower-case letters ('a'
to 'z'
), blank space (' '
) or a special character
('#'
). Also, the previously typed sentence should be recorded in your
system. The output will be the top 3 historical hot sentences that have prefix the
same as the part of sentence already typed.
Example:
Operation: AutocompleteSystem(["i love you", "island","ironman",
"i love leetcode"], [5,3,2,2])
The system have already tracked down the following sentences and their corresponding
times:
"i love you"
: 5
times
"island"
: 3
times
"ironman"
: 2
times
"i love leetcode"
: 2
times
Now, the user begins another search:
Operation: input('i')
Output: ["i love you", "island","i love leetcode"]
Explanation:
There are four sentences that have prefix "i"
. Among them, "ironman"
and "i love leetcode" have same hot degree. Since ' '
has
ASCII code 32 and 'r'
has ASCII code 114, "i love leetcode"
should be in front of "ironman". Also we only need to output top 3 hot sentences,
so "ironman" will be ignored.
Operation: input(' ')
Output: ["i love you","i love leetcode"]
Explanation:
There are only two sentences that have prefix "i "
.
Operation: input('a')
Output: []
Explanation:
There are no sentences that have prefix "i a"
.
Operation: input('#')
Output: []
Explanation:
The user finished the input, the sentence "i a"
should be saved as a
historical sentence in system. And the following input will be counted as a new search.
Note: