Lunski's Clutter

Given an integer array nums and an integer k, return the k most frequent elements. You may return the answer in any order.

Example 1:

1
2

Input: nums = [1,1,1,2,2,3], k = 2
Output: [1,2]

Example 2:

1
2

Input: nums = [1], k = 1
Output: [1]

我們進行了第二母語計畫，也讀了科技英文，下一步呢？

Given an integer n, return an array ans of length n + 1 such that for each i (0 <= i <= n), ans[i] is the number of 1’s in the binary representation of i.

Example 1:

1
2
3
4
5
6

Input: n = 2
Output: [0,1,1]
Explanation:
0 --> 0
1 --> 1
2 --> 10

Example 2:

1
2
3
4
5
6
7
8
9

Input: n = 5
Output: [0,1,1,2,1,2]
Explanation:
0 --> 0 // 2%2  
1 --> 1 // out[2/2]
2 --> 10 // out[2] = out[2/2]+2%2
3 --> 11 // out[3] = out[3/2]+3%2
4 --> 100
5 --> 101

Given a string s and a dictionary of strings wordDict, return true if s can be segmented into a space-separated sequence of one or more dictionary words.

Note that the same word in the dictionary may be reused multiple times in the segmentation.

Example 1:

1
2
3

Input: s = "leetcode", wordDict = ["leet","code"]
Output: true
Explanation: Return true because "leetcode" can be segmented as "leet code".

Example 2:

1
2
3
4

Input: s = "applepenapple", wordDict = ["apple","pen"]
Output: true
Explanation: Return true because "applepenapple" can be segmented as "apple pen apple".
Note that you are allowed to reuse a dictionary word.

Example 3:

1
2

Input: s = "catsandog", wordDict = ["cats","dog","sand","and","cat"]
Output: false

linked list of length n is given such that each node contains an additional random pointer, which could point to any node in the list, or null.

Construct a deep copy of the list. The deep copy should consist of exactly n brand new nodes, where each new node has its value set to the value of its corresponding original node. Both the next and random pointer of the new nodes should point to new nodes in the copied list such that the pointers in the original list and copied list represent the same list state. None of the pointers in the new list should point to nodes in the original list.

For example, if there are two nodes X and Y in the original list, where X.random –> Y, then for the corresponding two nodes x and y in the copied list, x.random –> y.

Return the head of the copied linked list.

The linked list is represented in the input/output as a list of n nodes. Each node is represented as a pair of [val, random_index] where:

val: an integer representing Node.val
random_index: the index of the node (range from 0 to n-1) that the random pointer points to, or null if it does not point to any node.
Your code will only be given the head of the original linked list.

Example 1:

1
2

Input: head = [[7,null],[13,0],[11,4],[10,2],[1,0]]
Output: [[7,null],[13,0],[11,4],[10,2],[1,0]]

Example 2:

1
2

Input: head = [[1,1],[2,1]]
Output: [[1,1],[2,1]]

Example 3:

1
2

Input: head = [[3,null],[3,0],[3,null]]
Output: [[3,null],[3,0],[3,null]]