Leetcode

Problem There are n seats and n students in a room. You are given an array seats of length n, where seats[i] is the position of the ith seat. You are also given the array students of length n, where students[j] is the position of the jth student. You may perform the following move any number of times: Increase or decrease the position of the ith student by 1 (i.e., moving the ith student from position x to x + 1 or x - 1) Return the minimum number of moves required to move each student to a seat such that no two students are in the same seat. ...

Problem Given two arrays arr1 and arr2, the elements of arr2 are distinct, and all elements in arr2 are also in arr1. Sort the elements of arr1 such that the relative ordering of items in arr1 are the same as in arr2. Elements that do not appear in arr2 should be placed at the end of arr1 in ascending order. Examples Example 1: Input: arr1 = [2,3,1,3,2,4,6,7,9,2,19], arr2 = [2,1,4,3,9,6] Output: [2,2,2,1,4,3,3,9,6,7,19] ...

Problem Design a max stack that supports push, pop, top, peekMax and popMax. push(x) – Push element x onto stack. pop() – Remove the element on top of the stack and return it. top() – Get the element on the top. peekMax() – Retrieve the maximum element in the stack. popMax() – Retrieve the maximum element in the stack, and remove it. If you find more than one maximum elements, only remove the top-most one. Examples Example 1: ...

Problem A school is trying to take an annual photo of all the students. The students are asked to stand in a single file line in non-decreasing order by height. Let this ordering be represented by the integer array expected where expected[i] is the expected height of the ith student in line. You are given an integer array heights representing the current order that the students are standing in. Each heights[i] is the height of the ith student in line (0-indexed). ...

Problem In English, we have a concept called root, which can be followed by some other word to form another longer word - let’s call this word derivative. For example, when the root "help" is followed by the word "ful", we can form a derivative "helpful". Given a dictionary consisting of many roots and a sentence consisting of words separated by spaces, replace all the derivatives in the sentence with the root forming it. If a derivative can be replaced by more than one root, replace it with the root that has the shortest length. ...

Problem Given a string array words, return an array of all characters that show up in all strings within the words (including duplicates). You may return the answer in any order. Examples Example 1: Input: words = ["bella","label","roller"] Output: ["e","l","l"] Example 2: Input: words = ["cool","lock","cook"] Output: ["c","o"] ...

Problem We are given a list nums of integers representing a list compressed with run-length encoding. Consider each adjacent pair of elements [freq, val] = [nums[2*i], nums[2*i+1]] (with i >= 0). For each such pair, there are freq elements with value val concatenated in a sublist. Concatenate all the sublists from left to right to generate the decompressed list. Return the decompressed list. Examples Example 1: ...

Problem You are given two strings s and t consisting of only lowercase English letters. Return the minimum number of characters that need to be appended to the end of s so that t becomes a subsequence of s. A subsequence is a string that can be derived from another string by deleting some or no characters without changing the order of the remaining characters. Examples Example 1: ...

Problem You are given a string s. The score of a string is defined as the sum of the absolute difference between the ASCII values of adjacent characters. Return the score of s. Examples Example 1: Input: s = "hello" Output: 13 Explanation: The ASCII values of the characters in s are: 'h' = 104, 'e' = 101, 'l' = 108, 'o' = 111. So, the score of s would be |104 - 101| + |101 - 108| + |108 - 108| + |108 - 111| = 3 + 7 + 0 + 3 = 13. ...

Problem Suppose you are given two lists of n points, one list p1, p2, ..., pn on the line y = 0 and the other list q1, q2, ..., qn on the line y = 1. Imagine a set of n line segments connecting each point pi to qi. Write an algorithm to determine how many pairs of the line segments intersect. ...