1.合并K个升序链表https://leetcode-cn.com/problems/merge-k-sorted-lists/
这题是leetcode的一个困难题
这里对将两个升序链表进行合并进行了复习，C++代码如下
1 ListNode* mergeTwoLists(ListNode *a, ListNode *b) { 2 if ((!a) || (!b)) return a ? a : b; 3 ListNode head, *tail = &head, *aPtr = a, *bPtr = b; 4 while (aPtr && bPtr) { 5 if (aPtr->val < bPtr->val) { 6 tail->next = aPtr; aPtr = aPtr->next; 7 } else { 8 tail->next = bPtr; bPtr = bPtr->next; 9 } 10 tail = tail->next; 11 } 12 tail->next = (aPtr ? aPtr : bPtr); 13 return head.next; 14 }
还学到了优先队列的思想，利用python的heapq模块，通过堆进行优先队列的实现
1 class ListNode: 2 def __init__(self, x): 3 self.val = x 4 self.next = None 5 6 class Solution: 7 def mergeKLists(self, lists: List[ListNode]) -> ListNode: 8 if not lists or len(lists) == 0: 9 return None 10 import heapq 11 heap = [] 12 # 首先 for 嵌套 while 就是将所有元素都取出放入堆中 13 for node in lists: 14 while node: 15 heapq.heappush(heap, node.val) 16 node = node.next 17 dummy = ListNode(None) 18 cur = dummy 19 # 依次将堆中的元素取出(因为是小顶堆，所以每次出来的都是目前堆中值最小的元素），然后重新构建一个列表返回 20 while heap: 21 temp_node = ListNode(heappop(heap)) 22 cur.next = temp_node 23 cur = temp_node 24 return dummy.next
2.删除排序数组中的重复项https://leetcode-cn.com/problems/remove-duplicates-from-sorted-array/
3.搜索旋转排序数组https://leetcode-cn.com/problems/search-in-rotated-sorted-array/
