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Leetcode with dani
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#Q20 #leet_codeQ15 Medium noscript. 3Sum
Given an integer array nums, return all the triplets [nums[i], nums[j], nums[k]] such that i != j, i != k, and j != k, and nums[i] + nums[j] + nums[k] == 0.

Notice that the solution set must not contain duplicate triplets.



Example 1:

Input: nums = [-1,0,1,2,-1,-4]
Output: [[-1,-1,2],[-1,0,1]]
Explanation:
nums[0] + nums[1] + nums[2] = (-1) + 0 + 1 = 0.
nums[1] + nums[2] + nums[4] = 0 + 1 + (-1) = 0.
nums[0] + nums[3] + nums[4] = (-1) + 2 + (-1) = 0.
The distinct triplets are [-1,0,1] and [-1,-1,2].
Notice that the order of the output and the order of the triplets does not matter.
Example 2:

Input: nums = [0,1,1]
Output: []
Explanation: The only possible triplet does not sum up to 0.
Example 3:

Input: nums = [0,0,0]
Output: [[0,0,0]]
Explanation: The only possible triplet sums up to 0.
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In my opinion, if you're preparing for an interview and have no enough time left, it’s best not to spend more than 45 minutes on a single problem. Instead, I believe you should focus on understanding different patterns and concepts. This approach can help you become more versatile and better equipped to tackle various questions during the interview. what do you think?
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Master Python Division: int(x / y) vs. x // y

Ever wonder about the difference between int(x / y) and x // y in Python? Let’s break it down! 🧠👇

int(x / y):
- Performs regular division first (x / y), giving a floating-point result.
- Then, truncates the result to an integer using int(), removing the decimal part.
- Example:
- int(7 / 3) ➡️ 2 (since 7 / 3 ≈ 2.3333, truncates to 2).
- int(-7 / 3) ➡️ -2 (since -7 / 3 ≈ -2.3333, truncates to -2).

x // y (Floor Division):
- Directly performs floor division, rounding down to the nearest integer.
- Example:
- 7 // 3 ➡️ 2 (largest integer ≤ 2.3333).
- -7 // 3 ➡️ -3 (largest integer ≤ -2.3333).

Key Differences:
- Rounding:
- int(x / y) truncates towards zero.
- x // y rounds down towards negative infinity.
- Negative numbers:
- For positive results, both are the same.
- For negative results, int(x / y) truncates, but x // y rounds down.

Example with Negative Numbers:
- int(-7 / 3) ➡️ -2
- -7 // 3 ➡️ -3
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Leetcode with dani
#Q20 #leet_codeQ15 Medium noscript. 3Sum Given an integer array nums, return all the triplets [nums[i], nums[j], nums[k]] such that i != j, i != k, and j != k, and nums[i] + nums[j] + nums[k] == 0. Notice that the solution set must not contain duplicate triplets.…
class Solution:
def threeSum(self, nums: List[int]) -> List[List[int]]:
nums = sorted(nums)
list1 = []
for i in range(len(nums)-1,-1,-1):
j = i - 1
left =0
if (i>1 and i!=(len(nums)-1) and nums[i]==nums[i+1]):
continue
while(j>-1 and left<=i-2 and j!=left):
total = nums[left] + nums[i] + nums[j]
if ( total)== 0:
list1.append([nums[left],nums[i],nums[j]])
left+=1
while(left<j and nums[left]==nums[left-1]):
left+=1
elif total > 0:
j-=1
else:
left+=1
return list1
after solving 3 sum try to solve the next question
#Q21 #leet_codeQ16 #3Sum_Closest
Medium

Given an integer array nums of length n and an integer target, find three integers in nums such that the sum is closest to target.

Return the sum of the three integers.

You may assume that each input would have exactly one solution.



Example 1:

Input: nums = [-1,2,1,-4], target = 1
Output: 2
Explanation: The sum that is closest to the target is 2. (-1 + 2 + 1 = 2).
Example 2:

Input: nums = [0,0,0], target = 1
Output: 0
Explanation: The sum that is closest to the target is 0. (0 + 0 + 0 = 0).


Constraints:

3 <= nums.length <= 500
-1000 <= nums[i] <= 1000
-104 <= target <= 104
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bubble sort
def bubbleSort(arr):
n = len(arr)

# Traverse through all array elements
for i in range(n):
swapped = False

# Last i elements are already in place
for j in range(0, n-i-1):

# Traverse the array from 0 to n-i-1
# Swap if the element found is greater
# than the next element
if arr[j] > arr[j+1]:
arr[j], arr[j+1] = arr[j+1], arr[j]
swapped = True
if (swapped == False):
break
insertion sort
def insertionSort(arr):
for i in range(1, len(arr)):
key = arr[i]
j = i - 1

# Move elements of arr[0..i-1], that are
# greater than key, to one position ahead
# of their current position
while j >= 0 and key < arr[j]:
arr[j + 1] = arr[j]
j -= 1
arr[j + 1] = key
Selection sort
def selection_sort(arr):
n = len(arr)
for i in range(n - 1):

# Assume the current position holds
# the minimum element
min_idx = i

# Iterate through the unsorted portion
# to find the actual minimum
for j in range(i + 1, n):
if arr[j] < arr[min_idx]:

# Update min_idx if a smaller element is found
min_idx = j

# Move minimum element to its
# correct position
arr[i], arr[min_idx] = arr[min_idx], arr[i]
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#Q21 #leet_codeQ1249 Medium noscript. Minimum Remove to Make Valid Parentheses
Given a string s of '(' , ')' and lowercase English characters.

Your task is to remove the minimum number of parentheses ( '(' or ')', in any positions ) so that the resulting parentheses string is valid and return any valid string.

Formally, a parentheses string is valid if and only if:

It is the empty string, contains only lowercase characters, or
It can be written as AB (A concatenated with B), where A and B are valid strings, or
It can be written as (A), where A is a valid string.


Example 1:

Input: s = "lee(t(c)o)de)"
Output: "lee(t(c)o)de"
Explanation: "lee(t(co)de)" , "lee(t(c)ode)" would also be accepted.
Example 2:

Input: s = "a)b(c)d"
Output: "ab(c)d"
Example 3:

Input: s = "))(("
Output: ""
Explanation: An empty string is also valid.


Constraints:

1 <= s.length <= 105
s[i] is either '(' , ')', or lowercase English letter.
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Forwarded from A2SV - Community
Hello fellow coders,

After a brief break, we've returned! Get ready for our fun weekly community coding contest happening every Saturday 🗓. It's your chance to compete with other awesome programmers, learn more about coding, and, most importantly, have a great time! 🥳

🏆 Contest Details:
📅 Date: November 2, 2024
Time: 6:00 PM
🔗 Link for Contest: Community Weekly Contest Return - Contest No 1

P.S. Remember to fill out this form to secure your spot for our upcoming community classes and lectures. It’s your golden ticket to enriching experiences you won’t want to miss. 📚
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Forwarded from LeetCode VIP
🏆 LeetCode 490. The Maze (Premium) 🏆

There's a ball in a maze with:
- Empty spaces (0) and walls (1).

The ball can roll in any direction:
- Up, down, left, or right 🌐

But here's the catch:
- It won't stop until it hits a wall! 🚧
- Once it stops, it can choose another direction to roll.

### Task 🎯
Given:
- An m x n maze
- The ball's starting position and a destination

Determine:
- Can the ball stop at the destination?
- If yes, return true. Otherwise, return false.

📝 Assumption: All borders of the maze are walls.

---

### Examples 🔍

Example 1:

Input: 
maze = [
[0,0,1,0,0],
[0,0,0,0,0],
[0,0,0,1,0],
[1,1,0,1,1],
[0,0,0,0,0]
],
start = [0,4],
destination = [4,4]

Output: true

Explanation: One possible path: left ➡️ down ➡️ left ➡️ down ➡️ right ➡️ down ➡️ right 🎯

---

Example 2:

Input:
maze = [
[0,0,1,0,0],
[0,0,0,0,0],
[0,0,0,1,0],
[1,1,0,1,1],
[0,0,0,0,0]
],
start = [0,4],
destination = [3,2]

Output: false

Explanation: The ball can pass through the destination, but it cannot stop there.

---

Example 3:

Input:
maze = [
[0,0,0,0,0],
[1,1,0,0,1],
[0,0,0,0,0],
[0,1,0,0,1],
[0,1,0,0,0]
],
start = [4,3],
destination = [0,1]

Output: false


---

### Constraints 📏
- Maze Dimensions: 1 ≤ m, n ≤ 100
- Cells contain only 0 (empty) or 1 (wall).
- Start and destination are in empty spaces and won’t initially overlap.

Can you solve it? 🤔
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Forwarded from LeetCode VIP
Forwarded from LeetCode VIP
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Leetcode with dani
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share ur answer in the comment section , i will check it
Given a number n, print all primes smaller than or equal to n. It is also given that n is a small number.

Example:

Input : n =10
Output : 2 3 5 7


Input : n = 20
Output: 2 3 5 7 11 13 17 19
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