qq_44822951的博客

class Solution { public TreeNode dfs(int[] nums ,int begin,int end) { if(begin>=0 && begin<= nums.length-1 && end>=0 && end<= nums.length-1 && begin <= end){ int mid = (end - begin.

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int lengthOfLIS(int* nums, int numsSize){ int count[10000]={0}; int i=0,j=0; count[0]=1; int max=0; int c=0; for(i=1;i<numsSize;i++){ count[i]=1; for(j=0;j<i;j++){ if(nums[j]<nums[i]){ c=1+cou.

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List + 小顶堆 + 栈（双端队列实现的栈）import java.util.*;class DinnerPlates { //list 栈 双端队列 //存放所有未满栈的下标的队列 private PriorityQueue<Integer> deque; //按顺序存放所有栈 private List<Deque<Integer>> list; //栈容量 private int cap...

TreeSetclass RangeModule { class Pair{ int left; int right; public Pair(int left,int right){ this.left = left; this.right = right; } } class PairComparator implements Comparator&l..

class MedianFinder { /** initialize your data structure here. */ private PriorityQueue<Integer> minHeap;//小顶堆 private PriorityQueue<Integer> maxHeap;//大顶堆 public MedianFinder() { minHeap = new PriorityQueue<Integer..

哈希表+优先队列class FreqStack { class Node{ //值的大小 int val; //值出现的频率 int freq; //值出现的时间 时间越大越靠近栈顶 int t; public Node(int val,int freq,int t){ this.val = val; this.freq = freq..

双端队列class RecentCounter { private Deque<Integer> deque; public RecentCounter() { deque = new LinkedList<>(); } public int ping(int t) { deque.offerLast(t); while(deque.size()!= 0 && t - 3..

超大数组class MyHashMap { private int[] map ; public MyHashMap() { map = new int[1000001]; Arrays.fill(map,-1); } public void put(int key, int value) { map[key] = value; } public int get(int key) { ..

优先队列class KthLargest { private PriorityQueue<Integer> queue; private int k; public KthLargest(int k, int[] nums) { queue = new PriorityQueue<Integer>(); this.k = k; for(int num : nums){ if(que..

单链表注意 第一次添加节点 或者 addAtIndex（添加的节点在末尾）deleteAtIndex（删除了末尾的节点） 都有可能造成尾指针的变动 要进行判断并且更新尾指针class MyLinkedList { class Node{ int val;//节点的值 Node next;//节点的next指针 public Node(int val){ this.val = val; } }..

前缀树+哈希表class MapSum { class TrieNode{ int val = 0; TrieNode[] child = new TrieNode[26]; } private TrieNode root; private Map<String,Integer> map; public MapSum() { root = new TrieNode(); map ..

class MyCircularDeque { //底层数组结构 private int[] deque; //头指针 private int head; //尾指针 private int tail; //队列中实际中存放的数的个数 private int size; //队列容量 private int capacity; public MyCircularDeque(int k) { dequ...

数组来实现队列class MyCircularQueue { private int[] queue;//队列数组 private int size;//队列中实际存放了多少元素 private int head;//头指针 private int tail;//尾指针 private int capacity;//队列固定大小 public MyCircularQueue(int k) { //队列固定大小为k thi..

哈希表+listclass RandomizedSet { //将值放入list中 为了可以随机取数 private List<Integer> list; //map的key是值 map的val是 值在list中的位置 //为了方便在o(1)时间内 插入删除值 private Map<Integer,Integer> map; public RandomizedSet() { list = new Array..

class NumArray { private int[] preSum; public NumArray(int[] nums) { int n = nums.length; preSum = new int[n+1]; for(int i = 0; i < n;i++) preSum[i+1] = preSum[i] + nums[i]; } public int sumRange(int...

用两个栈实现队列class MyQueue { //使用两个栈实现队列 //主栈 private Deque<Integer> deque1; //辅助栈 private Deque<Integer> deque2; public MyQueue() { deque1 = new LinkedList<>(); deque2 = new LinkedList<>();..

使用两个队列class MyStack { //使用两个队列实现栈 //主队列 private Deque<Integer> deque1; //辅助队列 private Deque<Integer> deque2; public MyStack() { deque1 = new LinkedList<>(); deque2 = new LinkedList<>();..

双端队列class PhoneDirectory { private Deque<Integer> deque; public PhoneDirectory(int maxNumbers) { deque = new LinkedList<>(); for(int i = 0; i < maxNumbers;i++) deque.offerLast(i); } publ...

双端队列class HitCounter { private Deque<Integer> deque; public HitCounter() { deque = new LinkedList<>(); } public void hit(int timestamp) { deque.offerLast(timestamp); } public int getHits(i..

哈希表class Logger { //printMap记录了字符串最后被打印的时间 private Map<String,Integer> printMap; public Logger() { printMap = new HashMap<>(); } public boolean shouldPrintMessage(int timestamp, String message) { if(..

class TicTacToe { private int[][] rows; private int[][] cols; private int[][] diags; private int n; public TicTacToe(int n) { //rows记录每个用户每行有多少棋子 rows = new int[3][n]; //cols记录每个用户每列有多少棋子 cols = new i...

class MovingAverage { private Deque<Integer> deque; private int size; int total; public MovingAverage(int size) { this.deque = new LinkedList<>(); this.size = size; total = 0; } public d..

class ValidWordAbbr { //存放单词缩写 对应的单词 Map<String, List<String>> map = new HashMap<>(); public ValidWordAbbr(String[] dictionary) { for(String word : dictionary){ String abbreviation = calabbreviation(wo...

双指针import java.util.NoSuchElementException;public class ZigzagIterator { private List<Integer> pv1; private List<Integer> pv2; private int pos1 ; private int pos2 ; private int num ; public ZigzagIterator(List<I...

class Vector2D { List<Integer> list = new ArrayList<>();//将二维向量存放到一维数组中 int pos = 0; public Vector2D(int[][] vec) { for(int[] v: vec){ for(int n : v){ list.add(n); } } }...

class Solution { public int shortestDistance(String[] wordsDict, String word1, String word2) { int index1 = -1;//word1最后出现的位置 int index2 = -1;//word2最后出现的位置 int minDistance = Integer.MAX_VALUE;//最短距离 for(i...

class Solution { public int[] smallestRange(List<List<Integer>> nums) { int k = nums.size();//共有k个整数列表 int n = 0;//共有n个数 for(int i = 0; i < k;i++){ n += nums.get(i).size(); } int[][] nums_ar.

大根堆+小根堆class MedianFinder { private PriorityQueue<Integer> maxHeap; private PriorityQueue<Integer> minHeap; public MedianFinder() { //大根堆 maxHeap = new PriorityQueue<>(new Comparator<Integer>(){ .

class Solution { public double[] medianSlidingWindow(int[] nums, int k) { DualHeap dh = new DualHeap(k); for (int i = 0; i < k; ++i) { dh.insert(nums[i]); } double[] ans = new double[nums.length - k + 1]..

哈希set保存窗口中字符的情况class Solution { public int lengthOfLongestSubstring(String s) { int len = s.length(); int left = 0; int right = 0; Set<Character> set = new HashSet<>(); int max = 0; for(rig..

LRU讲的很不错https://leetcode.cn/problems/lru-cache/solution/lru-ce-lue-xiang-jie-he-shi-xian-by-labuladong/哈希双链表class LRUCache { //明确LRU缓存要实现什么功能 //get(key) 如果key存在 获取其值 并把它设为最近使用过的节点 // put(key,val) 如果key存在 更改节点的值 并且把它设为最近使用过的节点 如果它不存在 缓存满了 先..

排序+单调栈class Solution { public int numberOfWeakCharacters(int[][] properties) { int n = properties.length;//一共有n个角色 //将角色按照攻击属性升序排列 Arrays.sort(properties,new Comparator<int[]>(){ public int compare(int[] p..

单调栈class Solution { public int maxWidthRamp(int[] nums) { int n = nums.length; Deque<Integer> deque = new LinkedList<>();//单调递减栈 for(int i = 0; i < n;i++){ if(deque.size() == 0 || nums[deque.pee.