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fix: handle single-node pops in linked-list deques (#1824)

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KingCrimsonJY
2026-10-10 19:18:20 +08:00
committed by GitHub
parent bd46fca90d
commit 5b279d48b3
12 changed files with 154 additions and 111 deletions
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codes/dart/chapter_stack_and_queue/linkedlist_deque.dart
+13 -11
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@@ -73,25 +73,27 @@ class LinkedListDeque {
return null;
}
final int val;
if (isFront) {
// 队首出队操作
// 队列长度为 1 时, 头尾指向同一节点
if (_queSize == 1) {
val = _front!.val;
_front = null;
_rear = null;
}
// 队首出队操作
else if (isFront) {
val = _front!.val; // 暂存头节点值
// 删除头节点
ListNode? fNext = _front!.next;
if (fNext != null) {
fNext.prev = null;
_front!.next = null;
}
fNext!.prev = null;
_front!.next = null;
_front = fNext; // 更新头节点
// 队尾出队操作
} else {
// 队尾出队操作
val = _rear!.val; // 暂存尾节点值
// 删除尾节点
ListNode? rPrev = _rear!.prev;
if (rPrev != null) {
rPrev.next = null;
_rear!.prev = null;
}
rPrev!.next = null;
_rear!.prev = null;
_rear = rPrev; // 更新尾节点
}
_queSize--; // 更新队列长度