Feb 4 · 2 min read · QUESTION: Given a signed 32-bit integer x, return x with its digits reversed. If reversing x causes the value to go outside the signed 32-bit integer range [-2<sup>31</sup>, 2<sup>31</sup> - 1], then return 0. Assume the environment does not allow yo...
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Dec 23, 2025 · 4 min read · QUESTION: 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 st...
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Dec 1, 2025 · 2 min read · Given an integer array nums containing distinct positive integers, find and return any number from the array that is neither the minimum nor the maximum value in the array, or -1 if there is no such number. Return the selected integer. Example 1: Inp...
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Nov 29, 2025 · 6 min read · Insertion sort is a simple comparison-based sorting algorithm that sorts by repeatedly inserting elements into their correct position. Let's explore how it works in detail. What is Insertion Sort? Insertion Sort is a comparison sort algorithm. It div...
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Nov 28, 2025 · 2 min read · QUESTION: Given an integer array nums, return true if any value appears at least twice in the array, and return false if every element is distinct. Example 1: Input: nums = [1,2,3,1] Output: true Explanation: The element 1 occurs at the indices 0 a...
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Nov 2, 2025 · 2 min read · You are given an array of integers arr[]. You have to reverse the given array. Note: Modify the array in place. Examples: Input: arr = [1, 4, 3, 2, 6, 5] Output: [5, 6, 2, 3, 4, 1] Explanation: The elements of the array are [1, 4, 3, 2, 6, 5]. After ...
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Oct 20, 2025 · 2 min read · Given an array arr[]. Your task is to find the minimum and maximum elements in the array. Examples: Input: arr[] = [1, 4, 3, -5, -4, 8, 6] Output: [-5, 8] Explanation: minimum and maximum elements of array are -5 and 8. Input: arr[] = [12, 3, 15, 7,...
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Oct 11, 2025 · 3 min read · Given an integer n, return true if it is a power of four. Otherwise, return false. An integer n is a power of four, if there exists an integer x such that n == 4<sup>x</sup>. Example 1: Input: n = 16 Output: true Example 2: Input: n = 5 Output: fals...
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Oct 10, 2025 · 3 min read · Given an integer n, return true if it is a power of three. Otherwise, return false. An integer n is a power of three, if there exists an integer x such that n == 3<sup>x</sup>. Example 1: Input: n = 27 Output: true Explanation: 27 = 33 Example 2: In...
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Oct 8, 2025 · 3 min read · Given an integer n, return true if it is a power of two. Otherwise, return false. An integer n is a power of two, if there exists an integer x such that n == 2<sup>x</sup>. Example 1: Input: n = 1 Output: true Explanation: 20 = 1 Example 2: Input: n...
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