sorting/insertion-sort/insertion-sort-list
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2023-12-01
Insertion Sort List
描述
Sort a linked list using insertion sort.
分析
无
代码
// Insertion Sort List
// 时间复杂度O(n^2),空间复杂度O(1)
public class Solution {
public ListNode insertionSortList(ListNode head) {
ListNode dummy = new ListNode(Integer.MIN_VALUE);
//dummy.next = head;
for (ListNode cur = head; cur != null;) {
ListNode pos = findInsertPos(dummy, cur.val);
ListNode tmp = cur.next;
cur.next = pos.next;
pos.next = cur;
cur = tmp;
}
return dummy.next;
}
ListNode findInsertPos(ListNode head, int x) {
ListNode pre = null;
for (ListNode cur = head; cur != null && cur.val <= x;
pre = cur, cur = cur.next)
;
return pre;
}
}
// Insertion Sort List
// 时间复杂度O(n^2),空间复杂度O(1)
class Solution {
public:
ListNode *insertionSortList(ListNode *head) {
ListNode dummy(INT_MIN);
//dummy.next = head;
for (ListNode *cur = head; cur != nullptr;) {
auto pos = findInsertPos(&dummy, cur->val);
ListNode *tmp = cur->next;
cur->next = pos->next;
pos->next = cur;
cur = tmp;
}
return dummy.next;
}
ListNode* findInsertPos(ListNode *head, int x) {
ListNode *pre = nullptr;
for (ListNode *cur = head; cur != nullptr && cur->val <= x;
pre = cur, cur = cur->next)
;
return pre;
}
};