170. Two Sum III - Data structure design

Design a data structure that accepts a stream of integers and checks if it has a pair of integers that sum up to a particular value.

Implement the TwoSum class:

• TwoSum() Initializes the TwoSum object, with an empty array initially.
• void add(int number) Adds number to the data structure.
• boolean find(int value) Returns true if there exists any pair of numbers whose sum is equal to value, otherwise, it returns false.

1037. Valid Boomerang

Given an array points where points[i] = [xi, yi] represents a point on the X-Y plane, return true if these points are a boomerang.

A boomerang is a set of three points that are all distinct and not in a straight line.

434. Number of Segments in a String

Given a string s, return the number of segments in the string.

A segment is defined to be a contiguous sequence of non-space characters.

408. Valid Word Abbreviation

A string can be abbreviated by replacing any number of non-adjacent, non-empty substrings with their lengths. The lengths should not have leading zeros.

For example, a string such as "substitution" could be abbreviated as (but not limited to):

• "s10n" ("s ubstitutio n")
• "sub4u4" ("sub stit u tion")
• "12" ("substitution")
• "su3i1u2on" ("su bst i t u ti on")
• "substitution" (no substrings replaced)

The following are not valid abbreviations:

• "s55n" ("s ubsti tutio n", the replaced substrings are adjacent)
• "s010n" (has leading zeros)
• "s0ubstitution" (replaces an empty substring)

Given a string word and an abbreviation abbr

A substring is a contiguous non-empty sequence of characters within a string.

2525. Categorize Box According to Criteria

Given four integers length, width, height, and mass, representing the dimensions and mass of a box, respectively, return a string representing the category of the box.

• The box is "Bulky" if:

  • Any of the dimensions of the box is greater or equal to 104.
  • Or, the volume of the box is greater or equal to 109.

• If the mass of the box is greater or equal to 100, it is "Heavy".

• If the box is both "Bulky" and "Heavy", then its category is "Both".

• If the box is neither "Bulky" nor "Heavy", then its category is "Neither".

• If the box is "Bulky" but not "Heavy", then its category is "Bulky".

• If the box is "Heavy" but not "Bulky", then its category is "Heavy".

Note that the volume of the box is the product of its length, width and height.

414. Third Maximum Number

Given an integer array nums, return the third distinct maximum number in this array. If the third maximum does not exist, return the maximum number.

941. Valid Mountain Array

Given an array of integers arr, return true if and only if it is a valid mountain array.

Recall that arr is a mountain array if and only if:

• arr.length >= 3

• There exists some i with 0 < i < arr.length - 1 such that:

  • arr[0] < arr[1] < ... < arr[i - 1] < arr[i]
  • arr[i] > arr[i + 1] > ... > arr[arr.length - 1]

914. X of a Kind in a Deck of Cards

You are given an integer array deck where deck[i] represents the number written on the ith card.

Partition the cards into one or more groups such that:

• Each group has exactly x cards where x > 1, and
• All the cards in one group have the same integer written on them.

Return true if such partition is possible, or false otherwise.

2047. Number of Valid Words in a Sentence

A sentence consists of lowercase letters ('a' to 'z'), digits ('0' to '9'), hyphens ('-'), punctuation marks ('!', '.', and ','), and spaces (' ') only. Each sentence can be broken down into one or more tokens separated by one or more spaces ' '.

A token is a valid word if all three of the following are true:

• It only contains lowercase letters, hyphens, and/or punctuation (no digits).
• There is at most one hyphen '-'. If present, it must be surrounded by lowercase characters ("a-b" is valid, but "-ab" and "ab-" are not valid).
• There is at most one punctuation mark. If present, it must be at the end of the token ("ab,", "cd!", and "." are valid, but "a!b" and "c.," are not valid).

Examples of valid words include "a-b.", "afad", "ba-c", "a!", and "!".

Given a string sentence, return the number of valid words in sentence.

1909. Remove One Element to Make the Array Strictly Increasing

nums, return true if it can be made strictly increasing after removing exactly one element, or false otherwise. If the array is already strictly increasing, return true.

The array nums``nums[i - 1] < nums[i] for each index (1 <= i < nums.length).