Installing Homebrew on a Mac

Installation Steps

• Open the Terminal app.
• Type ruby -e "$(curl -fsSL https://raw.githubusercontent.com/Homebrew/install/master/install)" 

It will ask for password provide your mac password. 

After it run and executed few scripts you should see 

==> Installation successful!

satyagokavarapu@Satyanarayanas-MacBook-Pro ~ % ruby -e "$(curl -fsSL https://raw.githubusercontent.com/Homebrew/install/master/install)"

Warning: The Ruby Homebrew installer is now deprecated and has been rewritten in

Bash. Please migrate to the following command:

  /bin/bash -c "$(curl -fsSL https://raw.githubusercontent.com/Homebrew/install/master/install.sh)"

Password:

==> This script will install:

/usr/local/bin/brew

/usr/local/share/doc/homebrew

/usr/local/share/man/man1/brew.1

/usr/local/share/zsh/site-functions/_brew

/usr/local/etc/bash_completion.d/brew

/usr/local/Homebrew

Press RETURN to continue or any other key to abort

==> Downloading and installing Homebrew...

remote: Enumerating objects: 192, done.

remote: Counting objects: 100% (192/192), done.

remote: Compressing objects: 100% (15/15), done.

remote: Total 266 (delta 184), reused 181 (delta 177), pack-reused 74

Receiving objects: 100% (266/266), 80.68 KiB | 519.00 KiB/s, done.

Resolving deltas: 100% (193/193), completed with 55 local objects.

From https://github.com/Homebrew/brew

 * [new branch]          issyl0-patch-1 -> origin/issyl0-patch-1

   9bbd866fc..f260b6e7b  master         -> origin/master

 * [new branch]          tapioca-update -> origin/tapioca-update

 * [new tag]             2.4.15         -> 2.4.15

 * [new tag]             2.4.16         -> 2.4.16

HEAD is now at f260b6e7b Merge pull request #8328 from reitermarkus/desc-cop

Updated 3 taps (homebrew/cask-versions, homebrew/core and homebrew/cask).

==> New Formulae

periscope                                                                                              sponge

==> Updated Formulae

act                 checkstyle          editorconfig        ghz-web             helm                libphonenumber      mutt                pdfcpu              scrypt              vim

anime-downloader    code-server         enchant             gitleaks            helmfile            librealsense        nasm                pgformatter         seal                wtf

babel               conan               eslint              gleam               hexedit             lmod                nativefier          pmd                 sqlite-utils        xmrig

ballerina           dartsim             exploitdb           gnupg               htop                logtalk             navi                pnpm                step                xxh

benthos             deno                fastlane            gomplate            ipython             lsd                 netlify-cli         ponyc               swiftformat         zbar

bundletool          diffoscope          feh                 google-java-format  ispc                mame                nuget               pulumi              talisman

cadence             duckdb              folly               gravity             jfrog-cli           meilisearch         owfs                qrencode            trafficserver

cartridge-cli       dvc                 gatsby-cli          harfbuzz            kustomize           mikutter            packer              rebar3              uptimed

cdktf               dxpy                ghz                 hcloud              liblouis            mockolo             patchelf            rom-tools           v8

==> New Casks

aleph-one                                flying-carpet                            nocturn                                  pb                                       toolreleases

==> Updated Casks

aerial                            cookie                            id3-editor                        microsoft-edge                    quail                             tg-pro

alt-tab                           datadog-agent                     ivideonclient                     missive                           redisinsight                      thunderbird

anki                              dbeaver-community                 jabref                            nextcloud                         ringcentral                       tuxera-ntfs

app-cleaner                       decrediton                        jamovi                            nrlquaker-winbox                  runjs                             visual-studio-code-insiders

aquaskk                           dropbox-beta                      jellyfin                          obsidian                          sabnzbd                           voov-meeting

beekeeper-studio                  elpass                            kafka-tool                        ocenaudio                         screen                            webcatalog

blender                           epichrome                         keka-beta                         oolite                            segger-embedded-studio-for-arm    webtorrent

blitz                             exodus                            keysmith                          pagico                            sensei                            whale

brave-browser-dev                 extraterm                         kubernetic                        pastebot                          signal-beta                       whatsapp

busycal                           feishu                            lark                              pcoipclient                       silentknight                      wormhole

busycontacts                      fsnotes                           lockrattler                       propresenter                      softorino-youtube-converter       yojimbo

c0re100-qbittorrent               funter                            loom                              prowritingaid                     stats                             zappy

cacher                            grids                             lrtimelapse                       proxyman                          superproductivity                 zotero

chromium                          hstracker                         marathon                          publish-or-perish                 swiftformat-for-xcode

clipgrab                          icollections                      metasploit                        qiyimedia                         telegram

==> Deleted Casks

alephone                                                                                               sound-blaster-command

==> Installation successful!

 

How to Update Homebrew on Mac

 Open terminal and type brew update command.

satyagokavarapu@Satyanarayanas-MacBook-Pro ~ % #brew update

Perform String Shifts Python

You are given a string s containing lowercase English letters, and a matrix shift, where shift[i] = [direction, amount]:

• direction can be 0 (for left shift) or 1 (for right shift). 
• amount is the amount by which string s is to be shifted.
• A left shift by 1 means remove the first character of s and append it to the end.
• Similarly, a right shift by 1 means remove the last character of s and add it to the beginning.

Return the final string after all operations.

Example 1:

Input: s = "abc", shift = [[0,1],[1,2]]
Output: "cab"
Explanation: 
[0,1] means shift to left by 1. "abc" -> "bca"
[1,2] means shift to right by 2. "bca" -> "cab"

class Solution:

    def stringShift(self, s: str, shift: List[List[int]]) -> str:

        l,ls,rs = len(s),0,0

        for direction , amount in shift:

            if direction == 0:

                ls+=amount

            else:

                rs+=amount

        ls = ls % l

        rs = rs % l

        if ls == rs:

            return s

        elif ls > rs:

            ls = ls -rs

            return s[ls:]+s[:ls]

        else:

            rs = rs -ls

            return s[-rs:]+s[:-rs]

            

        

        

        

        

            

            

            

Find the Difference Python

Given two strings s and t which consist of only lowercase letters.

String t is generated by random shuffling string s and then add one more letter at a random position.

Find the letter that was added in t.

Example:

Input:
s = "abcd"
t = "abcde"

Output:
e

Explanation:
'e' is the letter that was added.

Using sorting

class Solution:
    def findTheDifference(self, s: str, t: str) -> str:
        x = sorted(s)
        y = sorted(t)
        i = 0
        while i < len(x):
            if x[i] != y[i]:
                return y[i]
            i+=1
        return y[i]

Time Complexity : O(nlogn)

Space Complexity : O(1) sorting in python takes inplace so O(1)

Using Hashmap :

class Solution:
    def findTheDifference(self, s: str, t: str) -> str:
        counter_s = Counter(s)
        for ch in t:
            if ch not in counter_s or counter_s[ch] == 0:
                return ch
            else:
                counter_s[ch] -=1

Time Complexity : O(n)

Space Complexity : O(1)

Using Bit manipulation :

class Solution:
    def findTheDifference(self, s: str, t: str) -> str:
        res = 0
        for i in s:
            res ^= ord(i)
            
        for i in t:
            res ^= ord(i)
            
        return chr(res)

Time Complexity : O(n)

Space complexity : O(1)

Contains Duplicate II Python

Given an array of integers and an integer k, find out whether there are two distinct indices i and j in the array such that nums[i] = nums[j] and the absolute difference between i and j is at most k.

Example 1:

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

Example 2:

Input: nums = [1,0,1,1], k = 1
Output: true

Example 3:

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

Using Hashmap:

class Solution:
    def containsNearbyDuplicate(self, nums: List[int], k: int) -> bool:
        hashmap = {}
        for i in range(0,len(nums)):
            if nums[i] in hashmap and abs(hashmap[nums[i]] - i) <= k:
                return True
            else:
                hashmap[nums[i]] = i
        return False

Time Complexity : O(n)

Space Complexity :O(n,k) 

Number of Islands Python

Given a 2d grid map of '1's (land) and '0's (water), count the number of islands. An island is surrounded by water and is formed by connecting adjacent lands horizontally or vertically. You may assume all four edges of the grid are all surrounded by water.

Example 1:

Input:
11110
11010
11000
00000

Output: 1

Example 2:

Input:
11000
11000
00100
00011

Output: 3

Using DFS Method:

class Solution:
    def numIslands(self, grid: List[List[str]]) -> int:
        if not grid:
            return 0
        rows = len(grid)
        cols = len(grid[0])
        def dfs(i,j,grid):
            if i < 0 or i >= rows or j >= cols or j < 0 or grid[i][j] == '0':
                return 
            grid[i][j] = "0"
            dfs(i+1,j,grid)
            dfs(i-1,j,grid)
            dfs(i,j+1,grid)
            dfs(i,j-1,grid)
            return 1
        noOfIslands = 0
        for i in range(0,rows):
            for j in range(0,cols):
                if grid[i][j] == "1":
                    noOfIslands+=dfs(i,j,grid)
        return noOfIslands
        
        

Time Complexity : O(M * N)

Space Complexity : O(M * N) Worst case 

Reverse Integer Python

Given a 32-bit signed integer, reverse digits of an integer.

Example 1:

Input: 123
Output: 321

Example 2:

Input: -123
Output: -321

Example 3:

Input: 120
Output: 21

Note:
Assume we are dealing with an environment which could only store integers within the 32-bit signed integer range: [−231,  231 − 1]. For the purpose of this problem, assume that your function returns 0 when the reversed integer overflows.

class Solution:

    def reverse(self, x: int) -> int:

        sign = -1 if x < 0 else 1

        x *= sign

        res = 0

        while x > 0:

            res = (res * 10) + x % 10

            x = x // 10

        res*=sign

        return res if abs(res) <= (2 ** 31) else 0

            

Space Complexity : O(1)

Time Complexity : O(n)