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leetcode 1198 Premium question (https://github.com/doocs/leetcode/blob/main/solution/1100-1199/1198.Find%20Smallest%20Common%20Element%20in%20All%20Rows/README_EN.md)

G4 Interview Template

"""
Given a binary array data, return the minimum number of swaps required to group all 1’s present in the array together in any place in the array.


Example 1:

Input: data = [1,0,1,0,1]

Output: 1
Explanation: There are 3 ways to group all 1's together:
[1,1,1,0,0] using 1 swap.
[0,1,1,1,0] using 2 swaps.
[0,0,1,1,1] using 1 swap.
The minimum is 1.

Example 2:
Input: data = [0,0,0,1,0]
Output: 0
Explanation: Since there is only one 1 in the array, no swaps are needed.

Example 3:
Input: data = [1,0,1,0,1,0,0,1,1,0,1]
Output: 3
Explanation: One possible solution that uses 3 swaps is [0,0,0,0,0,1,1,1,1,1,1].


Constraints:

1 <= data.length <= 10^5
data[i] is either 0 or 1.


"""

Given an integer array nums of 2n integers, group these integers into n pairs (a1, b1), (a2, b2), ..., (an, bn) such that the sum of min(ai, bi) for all i is maximized.
Return the maximized sum.

Example 1:

Input: nums = [1,4,3,2]
Output: 4

Explanation: All possible pairings (ignoring the ordering of elements) are:
1. (1, 4), (2, 3) -> min(1, 4) + min(2, 3) = 1 + 2 = 3
2. (1, 3), (2, 4) -> min(1, 3) + min(2, 4) = 1 + 2 = 3
3. (1, 2), (3, 4) -> min(1, 2) + min(3, 4) = 1 + 3 = 4
So the maximum possible sum is 4.
Example 2:

Input: nums = [6,2,6,5,1,2]
Output: 9
Explanation: The optimal pairing is (2, 1), (2, 5), (6, 6). min(2, 1) + min(2, 5) + min(6, 6) = 1 + 2 + 6 = 9.
1 2 2 5 6 6


Constraints:

1 <= n <= 104
nums.length == 2 * n
-104 <= nums[i] <= 104

"""
Given an array of integer arrays arrays where each arrays[i] is sorted in strictly increasing order, 
return an integer array representing the longest common subsequence among all the arrays.
A subsequence is a sequence that can be derived from another sequence by deleting some elements 
(possibly none) without changing the order of the remaining elements.
 
Example 1:
Input: arrays = [[1,3,4],
                 [1,4,7,9]]
Output: [1,4]
Explanation: The longest common subsequence in the two arrays is [1,4].

Example 2:
Input: arrays = [[2,3,6,8],
                 [1,2,3,5,6,7,10],
                 [2,3,4,6,9]]
Output: [2,3,6]
Explanation: The longest common subsequence in all three arrays is [2,3,6].

Example 3:
Input: arrays = [[1,2,3,4,5],
                 [6,7,8]]
Output: []
Explanation: There is no common subsequence between the two arrays.
"""

result = []
for char in string:
    result.append(char)
final_string = ''.join(result)

Today's Interview Question
You are given a string s, which contains stars *.

In one operation, you can:

Choose a star in s.
Remove the closest non-star character to its left, as well as remove the star itself.
Return the string after all stars have been removed.

Note:

The input will be generated such that the operation is always possible.
It can be shown that the resulting string will always be unique.


Example 1:
Input: s = "leet**cod*e"
Output: "lecoe"
Explanation: Performing the removals from left to right:
- The closest character to the 1st star is 't' in "leet**cod*e". s becomes "lee*cod*e".
- The closest character to the 2nd star is 'e' in "lee*cod*e". s becomes "lecod*e".
- The closest character to the 3rd star is 'd' in "lecod*e". s becomes "lecoe".
There are no more stars, so we return "lecoe".

Example 2:
Input: s = "erase*****"
Output: ""
Explanation: The entire string is removed, so we return an empty string.

Constraints:

1 <= s.length <= 10**5
s consists of lowercase English letters and stars *.
The operation above can be performed on s.

def fun(s):
    stack = []
    for c in s:
        if c != "*":
            stack.append(c)
        else:
            stack.pop()
    return "".join(stack) 
print(fun("erase*****"))

A phrase is a palindrome if, after converting all uppercase letters into lowercase letters and removing all non-alphanumeric characters, it reads the same forward and backward. Alphanumeric characters include letters and numbers.

Given a string s, return true if it is a palindrome, or false otherwise.

 

Example 1:

Input: s = "A man, a plan, a canal: Panama"
Output: true
Explanation: "amanaplanacanalpanama" is a palindrome.
Example 2:

Input: s = "race a car"
Output: false
Explanation: "raceacar" is not a palindrome.
Example 3:

Input: s = " "
Output: true
Explanation: s is an empty string "" after removing non-alphanumeric characters.
Since an empty string reads the same forward and backward, it is a palindrome.
 

Constraints:

1 <= s.length <= 2 * 105
s consists only of printable ASCII characters.