2. Add Two Numbers #11
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skypenguins
reviewed
Jun 13, 2025
| ListNode* addTwoNumbers(ListNode* l1, ListNode* l2) { | ||
| ListNode dummy_head = ListNode(); | ||
| ListNode *result_tail = &dummy_head; | ||
| int curry = 0; |
skypenguins
reviewed
Jun 13, 2025
| int carry = 0; | ||
| while (l1 || l2 || carry) | ||
| { | ||
| int value = carry; |
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変数名 value は一般的すぎて、何の値が入っているのか想像しにくいと感じます。
skypenguins
reviewed
Jun 13, 2025
| value += l2->val; | ||
| l2 = l2->next; | ||
| } | ||
| carry = value / 10; |
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処理の始めから value に次々に l1 , l2 の値を足していく処理のようですが、変数の生存期間が長くてなんとなく頭の一時記憶を占める感覚があります。
nodchip
reviewed
Jun 14, 2025
| ```cpp | ||
| result_tail->next = new ListNode(value); | ||
| ``` | ||
| こんなんしていいの？これ気になった。 |
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なぜ気になったのか言語化することはできますか？
自分の場合は、関数の中で new で確保したメモリを、誰が解放するのか気になりました。 LeetCode の場合は、プログラムの終了時に OS が解放するのに任せるようです。実務のプログラムではメモリーリークとなるため、原則避けたほうがよいと思います。
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左辺はresult_tailの指すオブジェクトのListNode型のメンバーにアクセスしていて、new演算子はオブジェクトへのポインタ型(ListNode)を返すので論理的には問題ないかと思います。
oda
reviewed
Jun 16, 2025
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| https://leetcode.com/problems/add-two-numbers/description | ||
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| C++で書く練習。 |
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This Problem
https://leetcode.com/problems/add-two-numbers/description
Next Problem
https://leetcode.com/problems/longest-substring-without-repeating-characters/description