The Unplanned Marriage Meeting

 I was sleeping with a blanket over me when I suddenly heard the sound of uninvited guests at home. I thought it was okay, as my mum was there to attend to them, so I relaxed and went back to sleep. 

However, to my surprise, they were actually there to inquire about me. They had come to see me for their nephew. It was a big shock, as I was unprepared and hadn't taken a bath or changed out of my nightdress. They didn't give me a chance to prepare myself. 

My mum was also taken aback when the guests asked to see me. She urgently called for me to come quickly. I hastened to get ready, tidying my hair and spritzing some perfume to eliminate any evidence of not having taken a bath. 

When I went to meet the guests, I politely offered them water and tea, even though I'm not a fan of the latter. 

In India, it's customary to offer tea to guests, so I made an effort to make it, despite having not made tea for several years. 

The meeting went well, despite a humorous start. My arranged marriage matchmakers arrived and saw me dressed in a nightgown instead of looking my best.

Love Babbar's C++ DSA Lecture's Solutions

1. Lecture: 1 Homework Solutions
2. Lecture: 2 Homework Solutions
3. Lecture: 3 Homework Solutions
4. Lecture: 4 Homework Solutions
5. Lecture: 5 Homework Solutions
6. Lecture: 6 Homework Solutions
7. Lecture: 7 Homework Solutions

Homework of Video 4 ( Solving Pattern Questions (Part-2) ) - Love babbar

1. Write a program to print this pattern:

1

2 3

4 5 6

7 8 9 10

2. Write a program to print this pattern:

1

2 3

3 4 5

4 5 6 7

3. Write a program to print this pattern:

A B C

A B C

A B C

4. Write a program to print this pattern:

A B C

D E F

G H I

5. Write a program to print this pattern:

A B C

B C D

C D E

6. Write a program to print this triangular pattern:

A

B B

C C C

7. Write a program to print this triangular pattern:

D

C D

B C D

A B C D

8. Write a program to print this square matrix pattern:

****

***

**

*

9. Write a program to print this square matrix pattern:

****

***

**

*

10. Write a program to print this square matrix pattern:

1111

222

33

4

11. Write a program to print this square matrix pattern:

1

22

333

4444

12. Write a program to print this square matrix pattern:

1234

234

34

4

13. Write a program to print this square matrix pattern:

1

23

456

78910

14. Write a program to print this square matrix pattern:

1234554321

1234**4321

123****321

12******21

1********1

Homework of Video 3 ( If-Else, While loop & Lots of Patterns (Part-1) ) - Love babbar

1. Why do we write namespace std & iostream as the program's header?

Ans. These are pre-built libraries where a code related to performing a certain task is placed So that, C++ can work effectively.

a. Using namespace std: There are a bunch of namespaces & out of them we are using std that makes the computer know that we are using cout. Basically, an identifier conflict resolver.

b. #include <iostream> : This header contains the programs of input & output functions like cout,cin etc. #include asks to include iostream

2. Guess the output :

Ans: NINEYPOSITIVE

Ans: 3

Ans: Love24

3. Write a code that accepts char ch. 

• Prints this is the lowercase or small case if lies in between 'a' - 'z'
• Prints this is uppercase  if lies in between 'A' - 'Z'
• Prints this is numeric if lies in between '0' - '9'

4. Input N and print the sum of all the even numbers lying in 1 to N.

5.  Write a program to convert the temperature into:

• Fahrenheit to celsius
• Celsius to Fahrenheit

Homework of Video 1(Intro to Programming & Flowcharts)- Love babbar

Python Mail Merge Project - Automating Recipient Writing in a Letter

Project Description:

1. Automates the recipient writing part in the same letter.
2. Recipient names are given in a separate file named invited_names.txt
3. A sample letter is given in a separate file named starting_letter.txt
4. Code is to be written inside main.py whose purpose is to fetch the sample letter, replace the [name] in a sample letter with recipient names &  generate an individual letter following this naming convention: letter_for_{recipient_name}.txt
5. The number of names given in invited_names.txt file generates a similar number of letters. Suppose, 5 names are given in invited_names.txt then, 5 letters will be generated.

Folder Structure:

Output:

./Input/Letters/starting_letter.txt

Dear [name], You are invited to my birthday this Saturday. Hope you can make it! Engineer Bae

./Input/Names/invited_names.txt

Aang Zuko Appa Katara Sokka Momo Uncle Iroh Toph

./Output/ReadyToSend/example.txt

Dear Aang, You are invited to my birthday this Saturday. Hope you can make it! Engineer Bae

main.py

with open("Input/Names/invited_names.txt") as name_file: names = name_file.readlines() # for each name in invited_names.txt with open("Input/Letters/starting_letter.txt", "r") as letter_file: letter_content = letter_file.read() print(type(letter_content)) for name in names: recipient = name.strip() # name.strip("\n") letter_name = f'letter_for_{recipient}.txt' new_letter = letter_content.replace("[name]", recipient) # Replace the [name] placeholder with the actual name. with open(f'Output/ReadyToSend/{letter_name}', "w") as file: # Save the letters in the folder "ReadyToSend". file.write(new_letter)

Crossing the Turtle : Python Turtle Project for Beginners

 

Game Rules:

1. One turtle of unique color can only move forward.
• Neither left nor right. Turtle cannot even move backward.    
2. Turtle has to save itself from the collision with cars.
3. If crosses all the cars, its level increases & along with all the car's speed!
4. Random count cars & each car of random color are coming from the left & right.
5. The scoreboard is maintained for every level.

How the game looks like?

main.py

import time import turtle from turtle import Screen from player import Player from car_manager import CarManager from scoreboard import Scoreboard import random #TODO 1. Move the turtle with keypress #TODO 2. Create & move the cars #TODO 3. Detect collision with car #TODO 4. Detect when turtle reaches the other side #TODO 5. Create a scoreboard screen = Screen() screen.setup(width=600, height=600) screen.title("Crossing the Turtle") screen.tracer(0) screen.bgcolor("sky blue") game_is_on = True player=Player() car=CarManager() scoreboard=Scoreboard() screen.listen() screen.onkey(player.move_forward,'Up') while game_is_on: time.sleep(0.1) screen.update() car.create_car() car.move_cars() # TODO 3. Detect collision with car for cars in car.all_cars: if cars.distance(player)<20: game_is_on=False scoreboard.write_game_over() for cars in car.all_forward_cars: if cars.distance(player)<20: game_is_on=False scoreboard.write_game_over() #TODO 4. Detect when sucessful crossing if player.is_at_finish_line(): player.got_to_start() car.level_up() scoreboard.increase_level() screen.exitonclick()

player.py

from turtle import Turtle STARTING_POSITION = (0, -280) MOVE_DISTANCE = 10 FINISH_LINE_Y = 280 class Player(Turtle): def __init__(self): super().__init__() self.shape('turtle') self.color("gray") self.penup() self.got_to_start() self.left(90) #or self.setheading(90) def move_forward(self): self.forward(MOVE_DISTANCE) def is_at_finish_line(self): if self.ycor() > FINISH_LINE_Y: return True else: return False def got_to_start(self): self.goto(STARTING_POSITION)

car_manager.py

from turtle import Turtle import random COLORS = ["red", "orange", "yellow", "green", "blue", "purple"] STARTING_MOVE_DISTANCE = 5 MOVE_INCREMENT = 10 class CarManager: def __init__(self): self.all_cars=[] self.all_forward_cars=[] self.car_speed=STARTING_MOVE_DISTANCE def create_car(self): random_chance=random.randint(1,6) if random_chance==1: new_car=Turtle("square") new_car.penup() new_car.shapesize(stretch_len=2,stretch_wid=1) new_car.color(random.choice(COLORS)) random_y=random.randint(-250,250) new_car.goto(300,random_y) self.all_cars.append(new_car) new_forward_car=Turtle("square") new_forward_car.penup() new_forward_car.shapesize(stretch_len=2,stretch_wid=1) new_forward_car.color(random.choice(COLORS)) random_y=random.randint(-250,250) new_forward_car.goto(-300,random_y) self.all_forward_cars.append(new_forward_car) def move_cars(self): for car in self.all_cars: car.backward(self.car_speed) for car in self.all_forward_cars: car.forward(self.car_speed) def level_up(self): self.car_speed+=MOVE_INCREMENT

scoreboard.py

class Scoreboard(Turtle): def __init__(self): super().__init__() self.level=1 self.hideturtle() self.penup() self.goto(-280,250) self.update_scoreboard() def update_scoreboard(self): self.clear() self.write(f"Level:{self.level}",align="left",font=FONT) def increase_level(self): self.level+=1 self.update_scoreboard() def write_game_over(self): self.goto(0,0) self.write("Game Over",align="center",font=FONT)

Blind 75 Must Do Leetcode Python 3 Solutions

Hashing to Solutions:

1. Two Sum
2. Longest Substring Without Repeating Characters
3. Longest Palindromic Substring
4. Container With Most Water
5. 3Sum
6. Remove Nth Node From End of List
7. Valid Parentheses
8. Merge Two Sorted Lists
9.  Merge k Sorted Lists
10. Search in Rotated Sorted Array
11. Combination Sum
12. Rotate Image
13. Group Anagrams
14. Maximum Subarray
15. Spiral Matrix
16. Jump Game
17. Merge Intervals
18. Insert Interval
19. Unique Paths
20. Climbing Stairs
21. Set Matrix Zeroes
22. Minimum Window Substring
23. Word Search
24. Decode Ways
25. Validate Binary Search Tree
26. Same Tree
27.  Binary Tree Level Order Traversal
28. Maximum Depth of Binary Tree
29. Construct Binary Tree from Preorder and Inorder Traversal
30. Best Time to Buy and Sell Stock
31. Binary Tree Maximum Path Sum
32. Valid Palindrome
33. Longest Consecutive Sequence
34. Clone Graph
35. Word Break
36. Linked List Cycle
37. Reorder List
38. Maximum Product Subarray
39. Find Minimum in Rotated Sorted Array
40. Reverse Bits
41. Number of 1 Bits
42. House Robber
43. Number of Islands
44. Reverse Linked List
45. Course Schedule
46. Implement Trie (Prefix Tree)
47. Design Add and Search Words Data Structure
48. Word Search II
49. House Robber II
50. Contains Duplicate
51. Invert Binary Tree
52. Kth Smallest Element in a BST
53.  Lowest Common Ancestor of a Binary Search Tree
54. Lowest Common Ancestor of a Binary Tree
55. Product of Array Except Self
56. Valid Anagram
57. Meeting Rooms
58. Meeting Rooms II
59. Graph Valid Tree
60. Missing Number
61. Alien Dictionary
62. Encode and Decode Strings
63. Find Median from Data Stream
64. Longest Increasing Subsequence
65. Coin Change
66. Number of Connected Components in an Undirected Graph
67. Counting Bits
68. Top K Frequent Elements
69. Sum of Two Integers
70. Pacific Atlantic Water Flow
71. Longest Repeating Character Replacement
72. Non-overlapping Intervals
73. Serialize and Deserialize BST
74. Subtree of Another Tree
75. Palindromic Substrings
76. Longest Common Subsequence

 1. Two Sum

This code looks through a list to find two different numbers that add up to a specific target number. It does this by using two loops. The first loop starts at the beginning of the list. For each number in the first loop, the second loop looks at the numbers that come after it in the list. If it finds two numbers that add up to the target, it gives back their positions in the list.

class Solution: def twoSum(self, nums: List[int], target: int) -> List[int]: for num_first in range(len(nums)): for num_second in range(num_first+1,len(nums)): if nums[num_first]+nums[num_second] == target: return [num_first,num_second]

Time Complexity: O(n^2)

This is because for each element in the list (and there are 'n' elements), we are potentially looking at every other element in the list to find a match (which in the worst case is 'n-1' other elements), resulting in 'n' times 'n-1' operations.

Space complexity: O(1)

This code only uses a fixed amount of extra space (for the indices), no matter how big the list gets.

 2. Longest Substring Without Repeating Characters

class Solution: def lengthOfLongestSubstring(self, s: str) -> int: last_idx = {} max_len = 0 # starting index of current # window to calculate max_len start_idx = 0 for i in range(0, len(s)): # Find the last index of str[i] # Update start_idx (starting index of current window) # as maximum of current value of start_idx and last # index plus 1 if s[i] in last_idx: start_idx = max(start_idx, last_idx[s[i]] + 1) # Update result if we get a larger window max_len = max(max_len, i-start_idx + 1) # Update last index of current char. last_idx[s[i]] = i return max_len

• Time Complexity: O(n + d) where n is the length of the input string and d is the number of characters in the input string alphabet. 
• Space Complexity: O(d)

Counting Valleys - Hackerrank Solution

 Check out the counting valleys question here: Hackerrank question

The picturization of the problem:

Suppose the input is: UDDDUDUU

Then, 

Answer: Valley level is 1. Because hiker stepped this way only.

To solve this problem:

Initially, assumed U = 1, D = -1 & altitude=0

Then, iterated till total steps-1. Whenever altitude(height) that is sea level is 0 & the last step is 'U" I have incremented the valley by 1 (because valley level is considered only when hiker's last step is 'U" & at the sea level).

When all the elements are traversed it returned the final valley's value that's our final result.

Solution:

def countingValleys(steps, path):

    # Write your code here

    

    altitude = 0

    valley = 0

    dict = {

        "U": 1,

        "D": -1

    }

    for eachstep in range(steps):

        altitude += dict[path[eachstep]] # calculating hiker's each step

        if altitude == 0 and path[eachstep] == "U":

            valley += 1

    return valley

Sales by Match -Hackerrank solution

Check out the question here - Sales by Match

def sockMerchant(n, ar):

    pairs = 0

    for element in set(ar):

        pairs += ar.count(element) // 2

    

    return pairs

if __name__ == '__main__':

    fptr = open(os.environ['OUTPUT_PATH'], 'w')

    n = int(input().strip())

    ar = list(map(int, input().rstrip().split()))

    result = sockMerchant(n, ar)

    fptr.write(str(result) + '\n')

    fptr.close()