高频题（0）
1. leetcode1419
leetcode1419
2. 设计user favorite./unfavorite games
需要支持几种queries,包括user>favorite games,(user,item)->favorited?,以及item->#of favorites.
3. 最长连续相同character
给一个小写字母字符串，返回最长连续相同character+长度，如果长度相同，取在字符串中出
现晚的
input: "aabbaaabbb"
output: "b3"
解释："aa""bb""aaa""bbb"都是连续相同，先选长的"aaa"和"bbb"，其中选出现晚的"bbb"，输出"b3"
现晚的
input: "aabbaaabbb"
output: "b3"
解释："aa""bb""aaa""bbb"都是连续相同，先选长的"aaa"和"bbb"，其中选出现晚的"bbb"，输出"b3"
4. Random Weighted Index Picker
You are given a 0-indexed array of positive integers w where w[i] describes the weight of the ith index.
You need to implement the function pickIndex(), which randomly picks an index in the range [0, w.length - 1] (inclusive) and returns it. The probability of picking an index i is w[i] / sum(w).
- For example, if w = [1, 3], the probability of picking index 0 is 1 / (1 + 3) = 0.25 (i.e., 25%), and the probability of picking index 1 is 3 / (1 + 3) = 0.75 (i.e., 75%).
Example 1:
Input ["Solution","pickIndex"] [[[1]],[]] Output [null,0] Explanation Solution solution = new Solution([1]); solution.pickIndex(); // return 0. The only option is to return 0 since there is only one element in w.
Example 2:
Input ["Solution","pickIndex","pickIndex","pickIndex","pickIndex","pickIndex"] [[[1,3]],[],[],[],[],[]] Output [null,1,1,1,1,0] Explanation Solution solution = new Solution([1, 3]); solution.pickIndex(); // return 1. It is returning the second element (index = 1) that has a probability of 3/4. solution.pickIndex(); // return 1 solution.pickIndex(); // return 1 solution.pickIndex(); // return 1 solution.pickIndex(); // return 0. It is returning the first element (index = 0) that has a probability of 1/4. Since this is a randomization problem, multiple answers are allowed. All of the following outputs can be considered correct: [null,1,1,1,1,0] [null,1,1,1,1,1] [null,1,1,1,0,0] [null,1,1,1,0,1] [null,1,0,1,0,0] ...... and so on.
Constraints:
- 1 <= w.length <= 104
- 1 <= w[i] <= 105
- pickIndex will be called at most 104 times.
5. Text Justification Algorithm
Given an array of strings words and a width maxWidth, format the text such that each line has exactly maxWidth characters and is fully (left and right) justified.
You should pack your words in a greedy approach; that is, pack as many words as you can in each line. Pad extra spaces ' ' when necessary so that each line has exactly maxWidth characters.
Extra spaces between words should be distributed as evenly as possible. If the number of spaces on a line does not divide evenly between words, the empty slots on the left will be assigned more spaces than the slots on the right.
For the last line of text, it should be left-justified, and no extra space is inserted between words.
Note:
- A word is defined as a character sequence consisting of non-space characters only.
- Each word's length is guaranteed to be greater than 0 and not exceed maxWidth.
- The input array words contains at least one word.
Example 1:
Input: words = ["This", "is", "an", "example", "of", "text", "justification."], maxWidth = 16 Output: [ "This is an", "example of text", "justification. " ]
Example 2:
Input: words = ["What","must","be","acknowledgment","shall","be"], maxWidth = 16 Output: [ "What must be", "acknowledgment ", "shall be " ] Explanation: Note that the last line is "shall be " instead of "shall be", because the last line must be left-justified instead of fully-justified. Note that the second line is also left-justified because it contains only one word.
Example 3:
Input: words = ["Science","is","what","we","understand","well","enough","to","explain","to","a","computer.","Art","is","everything","else","we","do"], maxWidth = 20 Output: [ "Science is what we", "understand well", "enough to explain to", "a computer. Art is", "everything else we", "do " ]
Constraints:
- 1 <= words.length <= 300
- 1 <= words[i].length <= 20
- words[i] consists of only English letters and symbols.
- 1 <= maxWidth <= 100
- words[i].length <= maxWidth
