Freaks City

Problem Analysis Given n sequences (n ≤ 1e5) where each contains: Timestamp t (strict increasing) Count k (k ≤ 3e5) k integers Compute for each sequence x the count of unique integers across all sequences where (tx - t) < 86400 (24 hours in seconds). Constraints Partial Score (70pts): 1 ≤ n ≤ 100 Total k ≤ 100 Integer values ≤ 100 Timesta ...

Two Pointers Two pointers is a fundamental technique that uses two references to traverse data structures simultaneously. There are two primary variants: Collision Pointers (Converging Pointers): Both pointers start from opposite ends and move toward each other. Fast and Slow Pointers: Both pointers move in the same direction but at different s ...

LeetCode 209: Minimum Size Subarray Sum Problem Statement Given an array of n positive integers and a positive integer target, find the minimum length of a contiguous subaray whose sum is greater than or equal to target. Return 0 if no such subarray exists. Sliding Window Solution The sliding window technique provides an elegant O(n) solution. ...

A monotonic queue is a specialized data structure that maintains elements in either strictly increasing or decreasing order. Unlike standard queues, a monotonic queue allows operations at both the front and rear, functioning as a double-ended queue (deque) where elements are kept in sorted order. The Core Principle The fundamental insight behin ...

This article provides a concise summary of sliding window templates followed by practical examples. The recommended reading approach: skim the summary first, then study how each template is applied in the examples, and finally revisit the summary to solidify your understanding. Summary Problems that are well-suited for the sliding window techni ...

Problem AnalysisThe problem requires finding, for each position i in an array, the maximum value k such that the sum of elements in the left interval [i, i+k-1] and the sum of elements in the right interval [i+k, i+2*k-1] are both less than or equal to a given value s.Why Binary Search FailsAt first glance, one might consider using binary searc ...

Given two strings, we can determine if one contains a permutation of the other using a fixed-length sliding window approach. This technique efficiently checks for character matches by maintaining a window of characters and comparing frequency counts. Problem 1: Detecting Permutation Substring For the problem of determining if string s2 contanis ...

Problem Description Given an array of n positive integers and a positive integer target, find the length of the shortest continuous subarray whose sum is at least target. Return the length of this subarray. If no such subarray exists, return 0. Example 1: Input: target = 7, nums = [2,3,1,2,4,3] Output: 2 Explanation: The subarray [4,3] has the ...

Trpaping Rain Water Problem Given an array representing elevation maps, this problem calculates how much water can be trapped between bars after raining. vector<int> leftMax(n, 0); vector<int> rightMax(n, 0); if (n == 0) return 0; leftMax[0] = height[0]; rightMax[n-1] = height[n-1]; for (int i = 1; i < n; ++i) { leftMax[i] = ...

Problem Definition Given two strings s and p, identify every starting index within s where a substring contains the exact same characters as p with identical frequencies. Character order is irrelevant for matching purposes. Example: With s = "cbaebabacd" and p = "abc", the qualifying substrings apppear at indices 0 ("cb ...