2022 年 4月随笔档案 - 阳光明媚的菲越

896. Monotonic Array

摘要：My solution: class Solution { public boolean isMonotonic(int[] nums) { if(nums==null||nums.length<3){ return true; } int first = nums[0]; int second = 阅读全文

posted @ 2022-04-21 01:33 阳光明媚的菲越阅读(19) 评论(0) 推荐(0)

**316. Remove Duplicate Letters

摘要：class Solution { public String removeDuplicateLetters(String s) { int[] lastIndex = new int[26]; for (int i = 0; i < s.length(); i++){ lastIndex[s.cha 阅读全文

posted @ 2022-04-20 13:54 阳光明媚的菲越阅读(24) 评论(0) 推荐(0)

739. Daily Temperatures

摘要：This is the similar problem with: https://www.cnblogs.com/feiflytech/p/16169025.html class Solution { public int[] dailyTemperatures(int[] t) { int[] 阅读全文

posted @ 2022-04-20 13:43 阳光明媚的菲越阅读(23) 评论(0) 推荐(0)

1019. Next Greater Node In Linked List

摘要：This problem is as same as https://www.cnblogs.com/feiflytech/p/16169025.html class Solution { public int[] nextLargerNodes(ListNode head) { List<Inte 阅读全文

posted @ 2022-04-20 13:24 阳光明媚的菲越阅读(20) 评论(0) 推荐(0)

556. Next Greater Element III

摘要：This is a similiar problem with https://www.cnblogs.com/feiflytech/p/15862432.html The only differences are: 1. If no larger number can be returned, t 阅读全文

posted @ 2022-04-20 12:52 阳光明媚的菲越阅读(31) 评论(0) 推荐(0)

1944. Number of Visible People in a Queue

摘要：This is the similiar problem with: https://www.cnblogs.com/feiflytech/p/16168587.html and https://www.cnblogs.com/feiflytech/p/16169025.html class Sol 阅读全文

posted @ 2022-04-20 11:59 阳光明媚的菲越阅读(34) 评论(0) 推荐(0)

503. Next Greater Element II

摘要：Using stack, two pass: class Solution { public int[] nextGreaterElements(int[] nums) { Stack<Integer> stk = new Stack<>(); int[] res = new int[nums.le 阅读全文

posted @ 2022-04-20 11:11 阳光明媚的菲越阅读(19) 评论(0) 推荐(0)

496. Next Greater Element I

摘要：My solution, time complexity O(m*n): class Solution { public int[] nextGreaterElement(int[] nums1, int[] nums2) { Map<Integer, Integer> map = new Hash 阅读全文

posted @ 2022-04-20 09:52 阳光明媚的菲越阅读(34) 评论(0) 推荐(0)

34. Find First and Last Position of Element in Sorted Array

摘要：My binary search solution： class Solution { public int[] searchRange(int[] nums, int target) { if(nums==null || nums.length==0) return new int[]{-1,-1 阅读全文

posted @ 2022-04-20 07:25 阳光明媚的菲越阅读(26) 评论(0) 推荐(0)

22. Generate Parentheses

摘要：My back tracking solution: class Solution { List<String> res = new ArrayList<>(); public List<String> generateParenthesis(int n) { backTracking(n, 0 , 阅读全文

posted @ 2022-04-19 11:23 阳光明媚的菲越阅读(32) 评论(0) 推荐(0)

856. Score of Parentheses

摘要：Stack solution: class Solution { public int scoreOfParentheses(String s) { Stack<Integer> st = new Stack<>(); int score = 0; for(int i = 0; i < s.leng 阅读全文

posted @ 2022-04-19 10:19 阳光明媚的菲越阅读(24) 评论(0) 推荐(0)

311. Sparse Matrix Multiplication

摘要：My first solution, time complexityO(m*n), where m is the cell number of mat1, and n is the cell number of mat2: class Solution { public int[][] multip 阅读全文

posted @ 2022-04-19 08:15 阳光明媚的菲越阅读(28) 评论(0) 推荐(0)

1539. Kth Missing Positive Number

摘要：My first binary search solution: class Solution { public int findKthPositive(int[] arr, int k) { int l=0, r = arr.length-1; while(l+1<r){ int mid = (l 阅读全文

posted @ 2022-04-19 06:53 阳光明媚的菲越阅读(23) 评论(0) 推荐(0)

1060. Missing Element in Sorted Array

摘要：My solution: class Solution { public int missingElement(int[] nums, int k) { int i=1; for(;i<nums.length;i++){ int diff = nums[i]-nums[i-1]-1; if(diff 阅读全文

posted @ 2022-04-14 11:43 阳光明媚的菲越阅读(25) 评论(0) 推荐(0)

348. Design Tic-Tac-Toe

摘要：class TicTacToe { int n; int[] rows; int[] cols; int diag=0; int antiDiag = 0; public TicTacToe(int n) { this.n = n; rows = new int[n]; cols = new int 阅读全文

posted @ 2022-04-14 05:29 阳光明媚的菲越阅读(27) 评论(0) 推荐(0)

863. All Nodes Distance K in Binary Tree

摘要：The key to solve this problem is to find the path from root to target, and put the length to target of every node from root to target to a map. Then e 阅读全文

posted @ 2022-04-14 05:11 阳光明媚的菲越阅读(27) 评论(0) 推荐(0)

270. Closest Binary Search Tree Value

摘要：PreOrder: class Solution { double min = Integer.MAX_VALUE; int val; public int closestValue(TreeNode root, double target) { preOrder(root, target); re 阅读全文

posted @ 2022-04-14 02:47 阳光明媚的菲越阅读(19) 评论(0) 推荐(0)

616. Add Bold Tag in String

摘要：This is a merge interval's variety: class Solution { public String addBoldTag(String s, String[] words) { List<int[]> intervals = new ArrayList<>(); f 阅读全文

posted @ 2022-04-14 02:29 阳光明媚的菲越阅读(31) 评论(0) 推荐(0)

536. Construct Binary Tree from String

摘要：My solution, using stack: /** * Definition for a binary tree node. * public class TreeNode { * int val; * TreeNode left; * TreeNode right; * TreeNode( 阅读全文

posted @ 2022-04-12 12:34 阳光明媚的菲越阅读(27) 评论(0) 推荐(0)

778. Swim in Rising Water

摘要：BFS, using PriorityQueue to poll out the smallest number every time. The largest number you get will be the result. class Solution { public int swimIn 阅读全文

posted @ 2022-04-12 07:30 阳光明媚的菲越阅读(17) 评论(0) 推荐(0)

273. Integer to English Words

摘要：class Solution { private String[] lessThanTwenty = { "", "One", "Two", "Three", "Four", "Five", "Six", "Seven", "Eight", "Nine", "Ten", "Eleven", "Twe 阅读全文

posted @ 2022-04-12 07:04 阳光明媚的菲越阅读(31) 评论(0) 推荐(0)

133. Clone Graph

摘要：This problem remember one thing, using HashMap as data structure: class Solution { Map<Integer, Node> map = new HashMap<>(); public Node cloneGraph(No 阅读全文

posted @ 2022-04-12 07:03 阳光明媚的菲越阅读(21) 评论(0) 推荐(0)

129. Sum Root to Leaf Numbers

摘要：My first solution: class Solution { private int sum =0; public int sumNumbers(TreeNode root) { preOrder(root, ""); return sum; } private void preOrder 阅读全文

posted @ 2022-04-12 04:48 阳光明媚的菲越阅读(19) 评论(0) 推荐(0)

140. Word Break II

摘要：My back tracking solution1: class Solution { List<String> res = new ArrayList<>(); Set<String> set = new HashSet<>(); public List<String> wordBreak(St 阅读全文

posted @ 2022-04-12 04:17 阳光明媚的菲越阅读(29) 评论(0) 推荐(0)

1868. Product of Two Run-Length Encoded Arrays

摘要：My Solution: class Solution { public List<List<Integer>> findRLEArray(int[][] encoded1, int[][] encoded2) { int i=0,j=0; List<int[]> list = new ArrayL 阅读全文

posted @ 2022-04-12 04:01 阳光明媚的菲越阅读(32) 评论(0) 推荐(0)

515. Find Largest Value in Each Tree Row

摘要：My BFS solution: /** * Definition for a binary tree node. * public class TreeNode { * int val; * TreeNode left; * TreeNode right; * TreeNode() {} * Tr 阅读全文

posted @ 2022-04-12 01:22 阳光明媚的菲越阅读(27) 评论(0) 推荐(0)

246. Strobogrammatic Number

摘要：class Solution { public boolean isStrobogrammatic(String num) { Map<Character, Character> map = new HashMap<>(); map.put('0', '0'); map.put('1', '1'); 阅读全文

posted @ 2022-04-09 13:34 阳光明媚的菲越阅读(38) 评论(0) 推荐(0)

986. Interval List Intersections

摘要：My PriorityQueue Solution: class Solution { public int[][] intervalIntersection(int[][] firstList, int[][] secondList) { PriorityQueue<int[]> pq1 = ne 阅读全文

posted @ 2022-04-09 13:16 阳光明媚的菲越阅读(23) 评论(0) 推荐(0)

23. Merge k Sorted Lists

摘要：My Solution 1: class Solution { public ListNode mergeKLists(ListNode[] lists) { PriorityQueue<ListNode> queue = new PriorityQueue<>((a,b)-> a.val-b.va 阅读全文

posted @ 2022-04-09 06:11 阳光明媚的菲越阅读(18) 评论(0) 推荐(0)

415. Add Strings

摘要：class Solution { public String addStrings(String num1, String num2) { StringBuilder res = new StringBuilder(); int carry = 0; int i=num1.length()-1, j 阅读全文

posted @ 2022-04-09 05:55 阳光明媚的菲越阅读(20) 评论(0) 推荐(0)

346. Moving Average from Data Stream

摘要：class MovingAverage { Queue<Integer> queue = new LinkedList<>(); int size = 0; double sum=0; public MovingAverage(int size) { this.size = size; } publ 阅读全文

posted @ 2022-04-09 05:25 阳光明媚的菲越阅读(26) 评论(0) 推荐(0)

125. Valid Palindrome

摘要：class Solution { public boolean isPalindrome(String s) { s= s.toLowerCase(); int i=0, j=s.length()-1; while(i<j){ char a = s.charAt(i); char b = s.cha 阅读全文

posted @ 2022-04-09 04:32 阳光明媚的菲越阅读(23) 评论(0) 推荐(0)

708. Insert into a Sorted Circular Linked List

摘要：We use two points to point to two successive nodes， we call them "pre" and "cur" We need to consider 3 situation need to be considered: 1. the inserte 阅读全文

posted @ 2022-04-09 02:34 阳光明媚的菲越阅读(26) 评论(0) 推荐(0)

721. Accounts Merge

摘要：The most important things to solve this problem are: recognizing this is a graph problem. Select a correct data structure to store the graph: Map<Stri 阅读全文

posted @ 2022-04-08 03:59 阳光明媚的菲越阅读(25) 评论(0) 推荐(0)

56. Merge Intervals

摘要：My PriorityQueue Solution: class Solution { public int[][] merge(int[][] intervals) { PriorityQueue<int[]> queue = new PriorityQueue<>((a,b)->a[0]-b[0 阅读全文

posted @ 2022-04-07 06:33 阳光明媚的菲越阅读(31) 评论(0) 推荐(0)

301. Remove Invalid Parentheses

摘要：Just use BFS to solve this problem: 1. put the s to queue 2. if s is not a valid string, then remove a '(' or ')', and then put to the queue. 3. once 阅读全文

posted @ 2022-04-07 02:42 阳光明媚的菲越阅读(39) 评论(0) 推荐(0)

65. Valid Number

摘要：For this problem, we need to consider the following cases: +23 - valid 23+5 - invalid 9e - invalid e6 - invalid 23e+5 - valid 9.6e2 - valid 9e6.2 - in 阅读全文

posted @ 2022-04-06 13:08 阳光明媚的菲越阅读(11) 评论(0) 推荐(0)