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leetcode 1346. Check If N and Its Double Exist 排序,双指针扫描,注意正负;哈希表
leetcode 1346. Check If N and Its Double Exist如果都是非负数的从小到大有序序列,从左往右i,j两个指针扫描,j为不满足2*a[i]<a[j]的下一个j。排序O(nlogn),扫描O(n)如果有正有负,分成两个序列,把负数序列反转、取相反数。class Solution {public: bool check_sorted(vector<int>& arr) {// sort(arr.begin(),arr.end()原创 2020-09-05 16:54:25 · 202 阅读 · 0 评论 -
leetcode 313. Super Ugly Number
313. Super Ugly Number遍历从小到大找ugly number,每个新的ugly number是primes中的素数乘积,必然是某个素数乘之前的某个ugly number。每个primes中的素数记录一个下标,对应将要乘的ugly number。每个primes中的素数,乘以之前的尽量小的ugly number,但如果之前某个ugly number能和该素数生成之前某个ugly number,则给该素数记录的接下来将要乘的ugly number下标+1。注意INT_MAX和long原创 2020-09-01 00:15:12 · 243 阅读 · 0 评论 -
leetcode 714. Best Time to Buy and Sell Stock with Transaction Fee 遍历、递推、状态转移
leetcode 714. Best Time to Buy and Sell Stock with Transaction Fee(未完待续)一开始的想法:遍历,低买高卖,考虑手续费,所以价差不超过手续费不卖,先跌后涨但跌幅不超过手续费不卖,示例正确但Wrong Answer。class Solution {public: int maxProfit(vector<int>& prices, int fee) { int len=prices.原创 2020-08-29 22:13:38 · 126 阅读 · 0 评论 -
leetcode 1171. Remove Zero Sum Consecutive Nodes from Linked List 前缀和
leetcode 1171. Remove Zero Sum Consecutive Nodes from Linked List/** * Definition for singly-linked list. * struct ListNode { * int val; * ListNode *next; * ListNode() : val(0), next(nullptr) {} * ListNode(int x) : val(x), next(nullp原创 2020-08-28 00:11:20 · 147 阅读 · 0 评论 -
leetcode 189. Rotate Array
leetcode 189. Rotate Array调库:class Solution {public: void rotate(vector<int>& nums, int k) { int len=nums.size(); k=k%len; vector<int> vec_a(nums.end()-k,nums.end()); vector<int> vec_b(nums原创 2020-08-26 22:37:29 · 100 阅读 · 0 评论 -
洛谷 P1309 瑞士轮 归并
洛谷 P1309 瑞士轮https://www.luogu.com.cn/problem/P1309每一轮快排,超时:# include<iostream># include<fstream># include<vector> # include<algorithm> using namespace std;class Athlete{public: int id,competence,score; Athlete(){} //原创 2020-08-26 19:47:39 · 166 阅读 · 0 评论 -
leetcode 1371. Find the Longest Substring Containing Vowels in Even Counts
Find the Longest Substring Containing Vowels in Even Counts用state表示[0,i]子字符串的状态,状态有5个二进制位,对应5个元音字母的奇偶性class Solution {public: int findTheLongestSubstring(string s) { int str_len...原创 2020-04-16 16:20:54 · 177 阅读 · 0 评论 -
洛谷 P1896 [SCOI2005]互不侵犯 递推/动归 (可状态压缩)
洛谷 P1896 [SCOI2005]互不侵犯题目描述在N×N的棋盘里面放K个国王,使他们互不攻击,共有多少种摆放方案。国王能攻击到它上下左右,以及左上左下右上右下八个方向上附近的各一个格子,共8个格子。输入格式只有一行,包含两个数N,K ( 1 <=N <=9, 0 <= K <= N * N)输出格式所得的方案数递推/动态规划只考虑一行,一行合法状态必须...原创 2020-04-19 00:06:03 · 204 阅读 · 0 评论