Problem Statement Minimum Knight Moves LeetCode Solution – In an infinite chessboard with coordinates from -infinity to +infinity, you have a knight at square [0, 0]. A knight has 8 possible moves it can make, as illustrated below. Each move is two squares in a cardinal direction, then one square in an orthogonal direction. Return the minimum number …
Problem Statement Minimum Number of Taps to Open to Water a Garden LeetCode Solution – There is a one-dimensional garden on the x-axis. The garden starts at the point 0 and ends at the point n. (i.e The length of the garden is n). There are n + 1 taps located at points [0, 1, …, n] in …
Problem Statement Flatten 2D Vector LeetCode Solution – Design an iterator to flatten a 2D vector. It should support the next and hasNext operations. Implement the Vector2D class: Vector2D(int[][] vec) initializes the object with the 2D vector vec. next() returns the next element from the 2D vector and moves the pointer one step forward. You may assume that all …
Problem Statement Alien Dictionary LeetCode Solution – There is a new alien language that uses the English alphabet. However, the order among the letters is unknown to you. You are given a list of strings words from the alien language’s dictionary, where the strings in words are sorted lexicographically by the rules of this new language. …
Problem Statement Product of Array Except Self LeetCode Solution – Given an integer array nums, return an array answer such that answer[i] is equal to the product of all the elements of nums except nums[i]. The product of any prefix or suffix of nums is guaranteed to fit in a 32-bit integer. You must write an algorithm that runs in O(n) time and without using the division …
Problem Statement Design Skiplist LeetCode Solution – Design a Skiplist without using any built-in libraries. A skip list is a data structure that takes O(log(n)) time to add, erase and search. Compared with the tree and red-black tree which has the same function and performance, the code length of Skiplist can be comparatively …
Problem Statement Permutation Sequence LeetCode Solution – The set [1, 2, 3, …, n] contains a total of n! unique permutations. By listing and labeling all of the permutations in order, we get the following sequence for n = 3: “123” “132” “213” “231” “312” “321” Given n and k, return the kth permutation sequence. Example Test Case 1: Input: n …
Problem Statement One Edit Distance LeetCode Solution – Given two strings s and t, return true if they are both one edit distance apart, otherwise return false. A string s is said to be one distance apart from a string t if you can: Insert exactly one character into s to get t. Delete exactly one character from s to get t. Replace exactly one character of s with a different character to get t. Input: …
Problem Statement The Implement Trie (Prefix Tree) LeetCode Solution – “Implement Trie (Prefix Tree)” asks you to implement the Trie Data Structure that performs inserting, searching and prefix searching efficiently. Example: Input: [“Trie”, “insert”, “search”, “search”, “startsWith”, “insert”, “search”] [[], [“apple”], [“apple”], [“app”], [“app”], [“app”], [“app”]] Output: [null, null, true, false, true, null, true] Explanation: After inserting all the strings, trie looks like this. Word apple is searched which …
Problem Statement Design Hit Counter LeetCode Solution – Design a hit counter which counts the number of hits received in the past 5 minutes (i.e., the past 300 seconds). Your system should accept a timestamp parameter (in seconds granularity), and you may assume that calls are being made to the system in chronological order (i.e., timestamp is monotonically increasing). …