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Posts tagged as “prefix”

花花酱 LeetCode 208. Implement Trie (Prefix Tree)

Problem:

Implement a trie with insertsearch, and startsWith methods.

Note:
You may assume that all inputs are consist of lowercase letters a-z.

Idea:




Tree/children array

 

 

Solution:

C++ / Array

 

C++ / hashmap

 

Java

 

Python 1:

 

Python 2:

 

花花酱 LeetCode 677. Map Sum Pairs

https://leetcode.com/problems/map-sum-pairs/description/

Problem:

Implement a MapSum class with insert, and sum methods.

For the method insert, you’ll be given a pair of (string, integer). The string represents the key and the integer represents the value. If the key already existed, then the original key-value pair will be overridden to the new one.

For the method sum, you’ll be given a string representing the prefix, and you need to return the sum of all the pairs’ value whose key starts with the prefix.

Example 1:

Idea:

Prefix tree



Solution 1

Solution 2:

with std::unique_ptr