katrina95的博客

Codeless Code Case1 Small Stuff

katrina95 — Sat, 25 Feb 2023 12:07:28 +0800

Codeless Code的译文和我对文章的理解

1109. Corporate Flight Bookings

katrina95 — Sat, 05 Oct 2019 07:25:52 +0800

There are n flights, and they are labeled from 1 to n. We have a list of flight bookings. The i-th booking bookings[i] = [i, j, k] means that we booked k seats from flights labeled i to j inclusive. ...

787. Cheapest Flights Within K Stops

katrina95 — Sat, 05 Oct 2019 07:10:44 +0800

There are n cities connected by m flights. Each fight starts from city u and arrives at v with a price w. Now given all the cities and flights, together with starting city src and the destination dst,...

KMP算法：两个字符串的匹配，S1里匹配S2

katrina95 — Fri, 04 Oct 2019 02:18:29 +0800

通过创建一个部分匹配表来优化指针后移的效率。 http://www.ruanyifeng.com/blog/2013/05/Knuth%E2%80%93Morris%E2%80%93Pratt_algorithm.html

647. Palindromic Substrings(java)

katrina95 — Thu, 03 Oct 2019 06:55:10 +0800

Given a string, your task is to count how many palindromic substrings in this string. The substrings with different start indexes or end indexes are counted as different substrings even they consist o...

685. Redundant Connection II(java)

katrina95 — Thu, 03 Oct 2019 05:37:16 +0800

In this problem, a rooted tree is a directed graph such that, there is exactly one node (the root) for which all other nodes are descendants of this node, plus every node has exactly one parent, excep...

684. Redundant Connection(java)

katrina95 — Thu, 03 Oct 2019 02:15:51 +0800

In this problem, a tree is an undirected graph that is connected and has no cycles. The given input is a graph that started as a tree with N nodes (with distinct values 1, 2, …, N), with one additiona...

355. Design Twitter

katrina95 — Thu, 26 Sep 2019 08:41:17 +0800

Design a simplified version of Twitter where users can post tweets, follow/unfollow another user and is able to see the 10 most recent tweets in the user’s news feed. Your design should support the fo...

约瑟夫环

katrina95 — Thu, 26 Sep 2019 05:34:18 +0800

约瑟夫问题约瑟夫问题是个著名的问题：N个人围成一圈，第一个人从1开始报数，报M的将被杀掉，下一个人接着从1开始报。如此反复，最后剩下一个，求最后的胜利者。例如只有三个人，把他们叫做A、B、C，他们围成一圈，从A开始报数，假设报2的人被杀掉。首先A开始报数，他报1。侥幸逃过一劫。然后轮到B报数，他报2。非常惨，他被杀了 C接着从1开始报数接着轮到A报数，他报2。也被杀死了。最终胜利者是C...

390. Elimination Game（约瑟夫环）

katrina95 — Thu, 26 Sep 2019 05:31:02 +0800

There is a list of sorted integers from 1 to n. Starting from left to right, remove the first number and every other number afterward until you reach the end of the list. Repeat the previous step agai...

60. Permutation Sequence

katrina95 — Wed, 25 Sep 2019 11:23:17 +0800

The set [1,2,3,…,n] contains a total of n! unique permutations. By listing and labeling all of the permutations in order, we get the following sequence for n = 3: “123” “132” “213” “231” “312” “321” G...

381. Insert Delete GetRandom O(1) - Duplicates allowed

katrina95 — Wed, 25 Sep 2019 05:14:02 +0800

Design a data structure that supports all following operations in average O(1) time. Note: Duplicate elements are allowed. insert(val): Inserts an item val to the collection. remove(val): Removes an i...

23. Merge k Sorted Lists

katrina95 — Wed, 25 Sep 2019 02:32:09 +0800

Merge k sorted linked lists and return it as one sorted list. Analyze and describe its complexity. Example: Input: [ 1->4->5, 1->3->4, 2->6 ] Output: 1->1->2->3->4-&g...

146. LRU Cache

katrina95 — Tue, 24 Sep 2019 15:20:02 +0800

Design and implement a data structure for Least Recently Used (LRU) cache. It should support the following operations: get and put. get(key) - Get the value (will always be positive) of the key if the...

380. Insert Delete GetRandom O(1)

katrina95 — Tue, 24 Sep 2019 14:02:43 +0800

Design a data structure that supports all following operations in average O(1) time. insert(val): Inserts an item val to the set if not already present. remove(val): Removes an item val from the set i...

432. All O`one Data Structure（java）

katrina95 — Tue, 24 Sep 2019 12:55:12 +0800

Implement a data structure supporting the following operations: Inc(Key) - Inserts a new key with value 1. Or increments an existing key by 1. Key is guaranteed to be a non-empty string. Dec(Key) - If...

二进制作为hashset存放visited,获取和设置第n位的值

katrina95 — Tue, 10 Sep 2019 13:03:18 +0800

获取x第n位的值：（x>>n） & 1 设置x第n位的值为1：x = x || 1<

53. Maximum Subarray(写1186顺便复习一下这道题的两种写法)

katrina95 — Mon, 09 Sep 2019 13:39:02 +0800

Given an integer array nums, find the contiguous subarray (containing at least one number) which has the largest sum and return its sum. Example: Input: [-2,1,-3,4,-1,2,1,-5,4], Output: 6 Explanation...

LeetCode 1186. Maximum Subarray Sum with One Deletion(java)

katrina95 — Mon, 09 Sep 2019 13:35:57 +0800

Given an array of integers, return the maximum sum for a non-empty subarray (contiguous elements) with at most one element deletion. In other words, you want to choose a subarray and optionally delete...

LeetCode 815. Bus Routes(java)

katrina95 — Mon, 09 Sep 2019 09:34:47 +0800

We have a list of bus routes. Each routes[i] is a bus route that the i-th bus repeats forever. For example if routes[0] = [1, 5, 7], this means that the first bus (0-th indexed) travels in the sequenc...