3. Longest Substring Without Repeating Characters #48
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oda
reviewed
Aug 16, 2025
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| ## 最終コード | ||
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| using_characters.size()をintにキャストせずにそのままmaxに渡すと、max関数にintとsize_t（leetcodeの環境ではunsigned longみたいです）が渡されることになって（少なくともleetcodeの環境上では）エラーになってしまいました。 |
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テンプレート引数の型推論に失敗しているので max のようにテンプレート引数を明示してやる手もありますね。
Owner
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なるほど、max<int>(max_length, using_characters.size())という感じでしょうか。そちらの方が良いかもしれません。
ryosuketc
reviewed
Aug 16, 2025
| class Solution { | ||
| public: | ||
| int lengthOfLongestSubstring(string s) { | ||
| unordered_set<char> using_characters; |
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used_characters の方が (英語として) 自然でしょうか。現在使っている文字、というニュアンスを強く出すなら characters_in_use とかですが、*_in_use という変数名はあまり見かけないような気もします。
huyfififi
approved these changes
Aug 16, 2025
| int substring_start = 0; | ||
| int max_substring_length = 0; | ||
| unordered_map<char, int> character_to_index; | ||
| for (int i = 0; i < s.size(); ++i) { |
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最終的なコードで使用されているendだと、ここのiの意味を考える手間が省けて嬉しいですよね。
tokuhirat
reviewed
Aug 17, 2025
| ++start; | ||
| } | ||
| using_characters.emplace(s[end]); | ||
| max_length = max(max_length, (int)using_characters.size()); |
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個人的には index の引き算をして文字列の長さを求めた方が自然な気がしました。
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https://leetcode.com/problems/longest-substring-without-repeating-characters/description/