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Another Interview Question
▎Problem Statement
You are given a string s consisting only of the letters 'a' and 'b', and an integer k. You need to find the minimum number of character changes needed to obtain a substring of length ≥ k where all characters are the same.
Test Cases
Here are some test cases to illustrate the problem:
▎Test Case 1
• Input: s = "aabbaa", k = 3
• Output: 1
• Explanation: The substring "aaa" can be formed by changing one 'b' to 'a'.
▎Test Case 2
• Input: s = "ababab", k = 4
• Output: 2
• Explanation: To form "aaaa" or "bbbb", you need to change two characters (e.g., "aaab" or "bbba").
▎Test Case 3
• Input: s = "aaaaaa", k = 2
• Output: 0
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sorry for the minor error on the test cases , here is the updated
Question: Count Substrings with Same Start and End Character
Given a string s consisting only of lowercase English letters, your task is to find the number of substrings that start and end with the same character.
Examples:
Input: "abcba"
Output: 7
Explanation: The substrings are: "a", "b", "c", "b", "a", "bcb", and "aba".
Input: "abacada"
Output: 13
Explanation: The substrings are: "a", "b", "a", "c", "a", "d", "a", "aba", "aca", "ada", "abaca", "abada", and "abacad".
Input: "a"
Output: 1
Explanation: The only substring is "a".
Input: "zzzz"
Output: 10
Explanation: The substrings are: "z", "z", "z", "z", "zz", "zz", "zz", "zzz", "zzz", and "zzzz".
Challenge:
Write a function that takes a string as input and returns the total count of substrings that start and end with the same character.
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@zprogramming_bot or if u have any question u can ask me and if u have interviewed before please send us the question
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Question: Maximum Sum Score of an Array
You are given a 0-indexed integer array
nums of length n. The sum score of nums at an index i (where 0 <= i < n) is defined as the maximum of:
• The sum of the first i + 1 elements of nums.
• The sum of the last n - i elements of nums.
Your task is to return the maximum sum score of nums at any index.
▎Examples:
1. Input: nums = [4, 3, -2, 5]
Output: 10
Explanation:
• At index 0: max(4, 4 + 3 - 2 + 5) = max(4, 10) = 10.
• At index 1: max(4 + 3, 3 - 2 + 5) = max(7, 6) = 7.
• At index 2: max(4 + 3 - 2, -2 + 5) = max(5, 3) = 5.
• At index 3: max(4 + 3 - 2 + 5, 5) = max(10, 5) = 10.
• The maximum sum score of nums is 10.
2. Input: nums = [-3, -5]
Output: -3
Explanation:
• At index 0: max(-3, -3 - 5) = max(-3, -8) = -3.
• At index 1: max(-3 - 5, -5) = max(-8, -5) = -5.
• The maximum sum score of nums is -3.
▎Challenge:
Write a function maximumSumScore(nums) that takes an integer array as input and returns the maximum sum score.1 262
Question: Count Substrings with Same Start and End Character
Given a string
s consisting only of lowercase English letters, your task is to find the number of substrings that start and end with the same character.
▎Examples:
1. Input: "abcba"
Output: 7
Explanation: The substrings are: "a", "b", "c", "b", "a", "bcb", and "abcba".
2. Input: "abacada"
Output: 9
Explanation: The substrings are: "a", "b", "a", "c", "a", "d", "aba", "aca", and "abaca".
3. Input: "a"
Output: 1
Explanation: The only substring is "a".
4. Input: "zzzz"
Output: 10
Explanation: All substrings start and end with 'z': "z", "z", "z", "z", "zz", "zz", "zz", "zz", "zzz", and "zzzz".
▎Challenge:
Write a function that takes a string as input and returns the total count of substrings that start and end with the same character.1 262
▎💰 Problem 322: Coin Change
Problem Statement:
You are given an integer array
coins representing coins of different denominations and an integer amount representing a total amount of money.
Your task is to return the fewest number of coins that you need to make up that amount. If that amount of money cannot be made up by any combination of the coins, return -1.
You may assume that you have an infinite number of each kind of coin.
▎Examples:
Example 1:
Input: coins = [1, 2, 5], amount = 11 Output: 3 Explanation: 11 can be made up with two 5's and one 1 (5 + 5 + 1).Example 2:
Input: coins = [2], amount = 3 Output: -1 Explanation: It is not possible to make up the amount 3 with only coin of denomination 2.Example 3:
Input: coins = [1], amount = 0 Output: 0 Explanation: No coins are needed to make up the amount 0.
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Question: Can You Make This String a Palindrome?
A palindrome is a string that reads the same forwards and backwards. Given a string, determine if it's possible to rearrange the characters to form a palindrome.
Examples:
1. Input:
"civic"
• Output: True
• Explanation: The string is already a palindrome.
2. Input: "ivicc"
• Output: True
• Explanation: Rearranging the characters can form the palindrome "civic".
3. Input: "hello"
• Output: False
• Explanation: No rearrangement can form a palindrome.
4. Input: "aabbcc"
• Output: True
• Explanation: Rearranging the characters can form the palindrome "abcba".
5. Input: "racecar"
• Output: True
• Explanation: The string is already a palindrome.
Challenge:
Write a function that takes a string as input and returns True if the string can be rearranged to form a palindrome, and False otherwise.1 262
238. Product of Array Except Self Difficulty: Medium Problem: Given an integer array nums, return an array answer such that answer[i] is the product of all elements of nums except nums[i]. Conditions: - The product of any prefix or suffix of nums is guaranteed to fit in a 32-bit integer. - Your algorithm must run in O(n) time and must not use the division operation. Examples: Input: nums = [1,2,3,4] Output: [24,12,8,6] Input: nums = [-1,1,0,-3,3] Output: [0,0,9,0,0] Constraints: 2 <= nums.length <= 10^5 -30 <= nums[i] <= 30 Can you solve it?
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**238. Product of Array Except Self** **Difficulty**: Medium **Problem**: Given an integer array `nums`, return an array `answer` such that `answer[i]` is the product of all elements of `nums` except `nums[i]`. **Conditions**: - The product of any prefix or suffix of `nums` is guaranteed to fit in a 32-bit integer. - Your algorithm must run in O(n) time and must not use the division operation. **Examples**: - Input: `nums = [1,2,3,4]` Output: `[24,12,8,6]` - Input: `nums = [-1,1,0,-3,3]` Output: `[0,0,9,0,0]` **Constraints**: - 2 ≤ nums.length ≤ 10⁵ - -30 ≤ nums[i] ≤ 30 Can you solve it?
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**238. Product of Array Except Self** 💡 **Difficulty**: Medium 🔍 **Problem**: Given an integer array `nums`, return an array `answer` such that `answer[i]` is the product of all elements of `nums` except `nums[i]`. 👉 **Conditions**: - The product of any prefix or suffix of `nums` is guaranteed to fit in a 32-bit integer. - Your algorithm must run in **O(n)** time and **must not use the division operation**. ### **Examples** **Input**: `nums = [1,2,3,4]` **Output**: `[24,12,8,6]` **Input**: `nums = [-1,1,0,-3,3]` **Output**: `[0,0,9,0,0]` ### **Constraints** - `2 <= nums.length <= 105` - `-30 <= nums[i] <= 30` Can you solve it? 🧩
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Repost from A2SV - Discussion
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 23, 2024
⏰ Time: 6:00 PM
🔗 Link for Contest: Community Weekly Contest Return - Contest No 3
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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🎯 Problem of the Day: Sort Colors
Problem Description
You are given an array
nums with \( n \) objects colored red, white, or blue. Sort the array in-place so that objects of the same color are adjacent, with the colors in the order red, white, and blue.
- Represent the colors using integers:
- 0 → Red
- 1 → White
- 2 → Blue
⚠️ Note: You must not use the library's sort function.
---
Example 1
Input:
nums = [2,0,2,1,1,0]Output:
[0,0,1,1,2,2]Example 2 Input:
nums = [2,0,1]Output:
[0,1,2]--- 📝 Practice Questions for A2SV Preparation 1. Core Problem: - Solve LeetCode 75: Sort Colors () using Dutch National Flag Algorithm for \( O(n) \) time complexity. 2. Related Problems: - LeetCode 215 : Kth Largest Element in an Array - LeetCode 347 : Top K Frequent Elements - LeetCode 56 : Merge Intervals 3. Challenge Problem: - LeetCode 88: Merge Sorted Array --- 💡 Tip: Use a two-pointer or three-pointer approach to keep track of boundaries for the different colors! Try to optimize your solution to \( O(n) \) in both time and space. 🧠 Share your solution and discuss your approach with the community! 🌟
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Repost from A2SV - Discussion
Hello G6 In-Person Education Applicants,
As you gear up for your interviews, we want to inform you about the key topics to focus on. These are the areas that will be covered during the interview:
- Sorting
- Two Pointers
- Sliding Window
- Prefix Sum
- Stacks and Queues
Best of luck with your preparation! Stay confident and ready to showcase your skills.
