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Posts tagged as “bit”

花花酱 LeetCode 1125. Smallest Sufficient Team

In a project, you have a list of required skills req_skills, and a list of people.  The i-th person people[i] contains a list of skills that person has.

Consider a sufficient team: a set of people such that for every required skill in req_skills, there is at least one person in the team who has that skill.  We can represent these teams by the index of each person: for example, team = [0, 1, 3] represents the people with skills people[0]people[1], and people[3].

Return any sufficient team of the smallest possible size, represented by the index of each person.

You may return the answer in any order.  It is guaranteed an answer exists.

Example 1:

Input: req_skills = ["java","nodejs","reactjs"], people = [["java"],["nodejs"],["nodejs","reactjs"]]
Output: [0,2]

Example 2:

Input: req_skills = ["algorithms","math","java","reactjs","csharp","aws"], people = [["algorithms","math","java"],["algorithms","math","reactjs"],["java","csharp","aws"],["reactjs","csharp"],["csharp","math"],["aws","java"]]
Output: [1,2]

Constraints:

  • 1 <= req_skills.length <= 16
  • 1 <= people.length <= 60
  • 1 <= people[i].length, req_skills[i].length, people[i][j].length <= 16
  • Elements of req_skills and people[i] are (respectively) distinct.
  • req_skills[i][j], people[i][j][k] are lowercase English letters.
  • It is guaranteed a sufficient team exists.

Solution: DP

C++/Array

C++/HashTable

花花酱 LeetCode 1073. Adding Two Negabinary Numbers

Given two numbers arr1 and arr2 in base -2, return the result of adding them together.

Each number is given in array format:  as an array of 0s and 1s, from most significant bit to least significant bit.  For example, arr = [1,1,0,1] represents the number (-2)^3 + (-2)^2 + (-2)^0 = -3.  A number arr in array format is also guaranteed to have no leading zeros: either arr == [0] or arr[0] == 1.

Return the result of adding arr1 and arr2 in the same format: as an array of 0s and 1s with no leading zeros.

Example 1:

Input: arr1 = [1,1,1,1,1], arr2 = [1,0,1]
Output: [1,0,0,0,0]
Explanation: arr1 represents 11, arr2 represents 5, the output represents 16.

Note:

  1. 1 <= arr1.length <= 1000
  2. 1 <= arr2.length <= 1000
  3. arr1 and arr2 have no leading zeros
  4. arr1[i] is 0 or 1
  5. arr2[i] is 0 or 1

Solution: Simulation

Time complexity: O(n)
Space complexity: O(n)

C++

花花酱 LeetCode 67. Add Binary

Given two binary strings, return their sum (also a binary string).

The input strings are both non-empty and contains only characters 1 or 0.

Example 1:

Input: a = "11", b = "1"
Output: "100"

Example 2:

Input: a = "1010", b = "1011"
Output: "10101"

Solution: Big integer

Similar to https://zxi.mytechroad.com/blog/math/leetcode-66-plus-one/

Time complexity: O(n)
Space complexity: O(n)

C++

花花酱 LeetCode 1012. Complement of Base 10 Integer

Every non-negative integer N has a binary representation.  For example, 5 can be represented as "101" in binary, 11 as "1011" in binary, and so on.  Note that except for N = 0, there are no leading zeroes in any binary representation.

The complement of a binary representation is the number in binary you get when changing every 1 to a 0 and 0 to a 1.  For example, the complement of "101" in binary is "010" in binary.

For a given number N in base-10, return the complement of it’s binary representation as a base-10 integer.

Example 1:

Input: 5
Output: 2
Explanation: 5 is "101" in binary, with complement "010" in binary, which is 2 in base-10.

Example 2:

Input: 7
Output: 0
Explanation: 7 is "111" in binary, with complement "000" in binary, which is 0 in base-10.

Example 3:

Input: 10
Output: 5
Explanation: 10 is "1010" in binary, with complement "0101" in binary, which is 5 in base-10.

Note:

  1. 0 <= N < 10^9

Solution: Bit

Find the smallest binary number c that is all 1s, (e.g. “111”, “11111”) that is greater or equal to N.
ans = C ^ N or C – N

Time complexity: O(log(n))
Space complexity: O(1)

C++

花花酱 LeetCode 78. Subsets

Given a set of distinct integers, nums, return all possible subsets (the power set).

Note: The solution set must not contain duplicate subsets.

Example:

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

Solution: Combination

Time complexity: O(2^n)
Space complexity: O(n)

Implemention 1: DFS

C++

Python3

Implementation 2: Binary

C++

Python3