OA Pattern : 3 DSA 65 minutes, 18 MCQs 20 minutes
MCQs were based on CS fundaments and ML
Problem 1: Minimum Swaps to Sort Non-Zeros (100 points)
You are given an array of integers, where some elements are zeros and others are non-zero integers. Your task is to find the minimum number of swaps required to sort the non-zero elements in ascending order, while keeping all zeros at the end of the array.
Rules:
- You can only swap a non-zero element with a zero.
Problem 2: Minimize Longest Continuous Sequence After Flipping (60 points)
You are given a string consisting only of the characters 'a' and 'b'. You can flip characters, meaning you can swap 'a' to 'b' and vice versa, at most k times.
Your task is to minimize the length of the longest continuous sequence of the same character (either 'a' or 'b') in the string, after performing at most k flips.
Problem 3: Max Score of Substrings (50 points)
You are given a string s and a number k. You need to calculate the maximum score of any substring of length k in the string. The score of a substring is calculated as follows:
For each character in the substring:
- Its "character value" raised to the power of its frequency in the substring.
The character values are as follows:
'a'= 1,'b'= 2, ...,'z'= 26.
Return the maximum score among all substrings of length k. Since the result can be large, return it modulo .
Example 1:
Input: s = "abaab", k = 2
Output: 3
Explanation: The substrings of length 2 are:
"ab" → score = 1^1 + 2^1 = 3
"ba" → score = 2^1 + 1^1 = 3
"aa" → score = 1^2 = 1
"ab" → score = 1^1 + 2^1 = 3
The maximum score is 3.If anyone has a solution or a detailed approach to solve these problems efficiently, please share it. I would appreciate any help or suggestions. Thank you in advance!