[Trie] Fix trie contains function for empty string #954
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Checklist
Description
Currently
Trie().contains(word: "", matchPrefix: true))will returnfalse, which is wrong since the root node of aTrieis considered an empty string. This PR fixes this bug. More information can be found here or by checking implementations ofTriedata structure in other languages.There is actually already a test written for this, which is failing at the moment. So this PR also makes tests for
Triedata structure to pass.What has been done
containsfunction to returntruefor empty stringTrieproject toSwift 5. No code changes were required.How to test
Open
Trie.xcodeprojand make sure project builds and tests are passing.