Blue Ocean

Give an array contains n+1 number which range from 1 to n. Find the duplicates. e.g. 1, 2, 3, 3 -> 3 1, 3, 2, 4, 3 -> 3 Requireme...

Recently I coded in JS a lot. Its simplicity to make writing code extremely concise.

Many questions looks pretty hard, and we came up lots of lines of code and tried to cover every corner cases. But in the end the perfect sol...

Convert a non-negative integer to its english words representation. Given input is guaranteed to be less than 2 31 - 1. For example, 123...

From leetcode Given a sorted positive integer array nums and an integer n , add/patch elements to the array such that any number in range ...

One way to serialize a binary tree is to use pre-order traversal. When we encounter a non-null node, we record the node's value. If it ...

One of straightforward implementation of LRUCache is to use JDK's LinkedHashMap. However to implement it correctly, overriding its remov...