81. 搜索旋转排序数组 II
自己做
解：二分查找
class Solution {
public:bool search(vector<int>& nums, int target) {int n = (int)nums.size();int begin = 0;int end = n - 1;sort(nums.begin(), nums.end());//调整边界if(target >= nums[0]){ //target如果存在，则必然存在于左边,调整右边界（end）到左边while(begin < end && nums[begin] > nums[end] && nums[end] > target){int mid = (begin + end) / 2; //新边界if(nums[begin] > nums[mid]) //新边界还在右边end = mid - 1;else //新边界在左边if(nums[mid] < target) //跳过头了begin = mid + 1;}}else{ //target如果存在，则必然存在于右边,调整右边界（end）到左边while(begin < end && nums[begin] > nums[end] && nums[begin] > target){int mid = (begin + end) / 2; //新边界if(nums[begin] > nums[mid]) //新边界还在左边begin = mid + 1;else //新边界在左边if(nums[mid] > target) //跳过头了end = mid - 1;}}//二分查找while(begin <= end){int mid = (begin + end) / 2;if(nums[mid] == target) //找到了return true;if(nums[mid] > target) //往小处找end = mid - 1;if(nums[mid] < target) //往大处找begin = mid + 1;}//没找到return false;}
};
82. 删除排序链表中的重复元素 II
自己做
解：计数法
/*** Definition for singly-linked list.* struct ListNode {* int val;* ListNode *next;* ListNode() : val(0), next(nullptr) {}* ListNode(int x) : val(x), next(nullptr) {}* ListNode(int x, ListNode *next) : val(x), next(next) {}* };*/
class Solution {
public:ListNode* deleteDuplicates(ListNode* head) {vector<int> count(200, 0); //计数数组ListNode* p = head;//遍历计数while(p != nullptr){count[p->val + 100]++;p = p->next;}//首先删除开头部分（涉及头结点更改）while(head != nullptr && count[head->val + 100] > 1)head = head->next;if(head == nullptr) //删完了return head;//删除结点p = head;ListNode* q = p->next;while(q != nullptr){if(count[q->val + 100] > 1)p->next = q->next;elsep = p->next;q = p->next;}return head;}
};
83. 删除排序链表中的重复元素
自己做
解：前后指针
/*** Definition for singly-linked list.* struct ListNode {* int val;* ListNode *next;* ListNode() : val(0), next(nullptr) {}* ListNode(int x) : val(x), next(nullptr) {}* ListNode(int x, ListNode *next) : val(x), next(next) {}* };*/
class Solution {
public:ListNode* deleteDuplicates(ListNode* head) {//删除开头重复部分while(head != nullptr && head->next != nullptr && head->val == head->next->val)head = head->next;if(head == nullptr) //删完了或者本身为空return head;//删除中间部分ListNode* p = head;while(p->next != nullptr){if(p->val == p->next->val) //有重复p->next = p->next->next;else //无重复p = p->next;}return head;}
};
