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Looking at this article, I can see it's about C++ but labeled as Python. I'll improve the structure, fix the HTML issues, and make it clearer while keeping the C++ content intact. A ternary expression uses the format condition ? value1 : value2. Given a string representing nested ternary expressions with 'T' (True) and 'F' (False), we need to evaluate the final result. Problem Constraints String length ≤ 10000 Conditional expressions group right-to-left Conditions are always 'T' or 'F', never digits Final result is always 'T' or 'F' For example, "T?T?F:T:T" evaluates to "F". ... Read More
Suppose we have a list of numbers called target. We start with a list X of the same length filled with 1s. We can perform the following operation repeatedly: select any index i in X and set X[i] to the current sum of all elements in X. The goal is to check whether X can be transformed into the target list. For example, if target = [5, 9, 3], we start with X = [1, 1, 1] (sum = 3). Update index 2: X = [1, 1, 3] (sum = 5). Update index 0: X = [5, 1, 3] ... Read More
Gray code is a binary numeral system where consecutive numbers differ by exactly one bit. For example, the gray code sequence starts as: 000, 001, 011, 010, 110, 111, 101, 100. Given a number n, we need to find the nth gray code in decimal representation. The key insight is that gray codes follow a recursive pattern where we can find the nth gray code by determining the highest power of 2 less than or equal to n, then recursively solving for the remaining part. Algorithm Steps To convert a number to its corresponding gray code position: ... Read More
Suppose we have a 2D matrix where each row contains two values [height, count] that indicates a person has given height and there are 'count' number of people in front of them that are at least as tall as them. When this queue is shuffled, we need to recover the original ordering. Problem Understanding Given a shuffled queue representation, we need to reconstruct the original queue order. Each person is represented as [height, count] where count is the number of people in front who are taller or equal in height. Example Input and Output Input ... Read More
Finding distinct quadruples from four arrays that sum to a target value is a common algorithmic problem. We can solve this efficiently using a hash map to store intermediate sums and reduce the time complexity from O(n⁴) to O(n²). Problem Understanding Given four arrays A, B, C, D and a target sum, we need to find the count of distinct quadruples (i, j, k, l) where A[i] + B[j] + C[k] + D[l] equals the target. For example, with A = [5, 4, 3], B = [8, 4], C = [6, 2], D = [4, 10], target ... Read More
We need to simulate the state of prison cells after k days. Each cell becomes occupied (1) if both adjacent cells have the same state, otherwise it becomes empty (0). The first and last cells are always empty since they don't have two neighbors. Understanding the Problem Given a binary list representing prison cells and a number k, we need to find the state after k days. The transformation rule is: If a cell has two neighbors with the same state (both 0 or both 1), it becomes occupied (1) Otherwise, it becomes empty (0) First ... Read More
Suppose we have a list of numbers called nums. We can partition the list into some individual sublists then sort each piece. We have to find the maximum number of sublists we can partition so that nums as a whole is sorted afterwards. So, if the input is like nums = [4, 3, 2, 1, 7, 5], then the output will be 2, as we can sort the sublists like [4, 3, 2, 1] and [7, 5]. Algorithm To solve this, we will follow these steps − count := 0 ... Read More
Suppose we have a string s, we have to find the number of ways we can partition the string such that each part is a palindrome. So, if the input is like s = "xyyx", then the output will be 3, as we have splits like: ["x", "yy", "x"], ["x", "y", "y", "x"], ["xyyx"]. Approach To solve this, we will use dynamic programming with the following steps − Create a table of size n + 1 initialized with 0, except table[0] = 1 For each position i, check all possible substrings ending at i If ... Read More
When working with strings that contain choices in square brackets, we need to generate all possible combinations. For example, [d|t|l]im[e|s] represents multiple possible strings where we can choose from the options within brackets. The pattern [a|b|c] means we can choose either a, b, or c. Our task is to find all possible strings by making these choices. Example For the input s = "[d|t|l]im[e|s]", the output will be ['dime', 'dims', 'lime', 'lims', 'time', 'tims']. Algorithm We'll use a recursive approach with backtracking ? If the string is empty, return ... Read More
Sometimes we need to minimize the maximum value in a list by performing a limited number of decrease operations. This problem requires finding the minimum possible maximum value after k operations where each operation subtracts 1 from any element. Problem Understanding Given a list of numbers and k operations, we can subtract 1 from any element k times. The goal is to minimize the maximum value in the resulting list. Example If we have nums = [3, 4, 6, 5] and k = 6 operations ? Decrease 6 three times: [3, 4, 3, 5] ... Read More