Introduction

In this blog post, we'll share the most commonly asked coding interview questions at Accolite. If you don't have months to study for your interviews, you can use AI tools like Chatmagic to generate solutions quickly and efficiently - helping you pass the interviews and get the job offer!

Problem #1: Remove Duplicates from Sorted Array II

Given an integer array nums sorted in non-decreasing order, remove some duplicates in-place such that each unique element appears at most twice. The relative order of the elements should be kept the same. Since it is impossible to change the length of the array in some languages, you must instead have the result be placed in the first part of the array nums. More formally, if there are k elements after removing the duplicates, then the first k elements of nums should hold the final result. It does not matter what you leave beyond the first k elements. Return k after placing the final result in the first k slots of nums. Do not allocate extra space for another array. You must do this by modifying the input array in-place with O(1) extra memory. Custom Judge: The judge will test your solution with the following code: int[] nums = [...]; // Input array int[] expectedNums = [...]; // The expected answer with correct length int k = removeDuplicates(nums); // Calls your implementation assert k == expectedNums.length; for (int i = 0; i < k; i++) { assert nums[i] == expectedNums[i]; } If all assertions pass, then your solution will be accepted. Example 1: Input: nums = [1,1,1,2,2,3] Output: 5, nums = [1,1,2,2,3,] Explanation: Your function should return k = 5, with the first five elements of nums being 1, 1, 2, 2 and 3 respectively. It does not matter what you leave beyond the returned k (hence they are underscores). Example 2: Input: nums = [0,0,1,1,1,1,2,3,3] Output: 7, nums = [0,0,1,1,2,3,3,,_] Explanation: Your function should return k = 7, with the first seven elements of nums being 0, 0, 1, 1, 2, 3 and 3 respectively. It does not matter what you leave beyond the returned k (hence they are underscores). Constraints: 1 <= nums.length <= 3 * 104 -104 <= nums[i] <= 104 nums is sorted in non-decreasing order.

Topics: Array, Two Pointers

Problem #2: Replace the Substring for Balanced String

You are given a string s of length n containing only four kinds of characters: 'Q', 'W', 'E', and 'R'. A string is said to be balanced if each of its characters appears n / 4 times where n is the length of the string. Return the minimum length of the substring that can be replaced with any other string of the same length to make s balanced. If s is already balanced, return 0. Example 1: Input: s = "QWER" Output: 0 Explanation: s is already balanced. Example 2: Input: s = "QQWE" Output: 1 Explanation: We need to replace a 'Q' to 'R', so that "RQWE" (or "QRWE") is balanced. Example 3: Input: s = "QQQW" Output: 2 Explanation: We can replace the first "QQ" to "ER". Constraints: n == s.length 4 <= n <= 105 n is a multiple of 4. s contains only 'Q', 'W', 'E', and 'R'.

Topics: String, Sliding Window

Problem #3: Asteroid Collision

We are given an array asteroids of integers representing asteroids in a row. The indices of the asteriod in the array represent their relative position in space. For each asteroid, the absolute value represents its size, and the sign represents its direction (positive meaning right, negative meaning left). Each asteroid moves at the same speed. Find out the state of the asteroids after all collisions. If two asteroids meet, the smaller one will explode. If both are the same size, both will explode. Two asteroids moving in the same direction will never meet. Example 1: Input: asteroids = [5,10,-5] Output: [5,10] Explanation: The 10 and -5 collide resulting in 10. The 5 and 10 never collide. Example 2: Input: asteroids = [8,-8] Output: [] Explanation: The 8 and -8 collide exploding each other. Example 3: Input: asteroids = [10,2,-5] Output: [10] Explanation: The 2 and -5 collide resulting in -5. The 10 and -5 collide resulting in 10. Constraints: 2 <= asteroids.length <= 104 -1000 <= asteroids[i] <= 1000 asteroids[i] != 0

Topics: Array, Stack, Simulation