Coding Interviews

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 operation.

Given an array of meeting time intervals intervals where intervals[i] = [starti, endi], return the minimum number of conference rooms required.

Given n pairs of parentheses, write a function to generate all combinations of well-formed parentheses.

Given an integer array nums and an integer k, return the k most frequent elements. You may return the answer in any order.

Given a string containing just the characters '(' and ')', return the length of the longest valid (well-formed) parentheses substring.

Given a string s containing just the characters '(', ')', '{', '}', '[' and ']', determine if the input string is valid.

An input string is valid if:

Open brackets must be closed by the same type of brackets.

Open brackets must be closed in the correct order.

Every close bracket has a corresponding open bracket of the same type.

You have k lists of sorted integers in non-decreasing order. Find the smallest range that includes at least one number from each of the k lists.

We define the range [a, b] is smaller than range [c, d] if b - a < d - c or a < c if b - a == d - c

Given a string s representing a valid expression, implement a basic calculator to evaluate it, and return the result of the evaluation.

Note: You are not allowed to use any built-in function which evaluates strings as mathematical expressions, such as eval().

Implement a class that can find the median of a stream of numbers. The following methods should exist on the class:

void addNum(int num) adds the integer num from the data stream to the data structure.

double findMedian() returns the median of all elements so far. Answers within 10-5 of the actual answer will be accepted.

You are given a 0-indexed array of integers nums of length n. You are initially positioned at nums[0].

Each element nums[i] represents the maximum length of a forward jump from index i. In other words, if you are at nums[i], you can jump to any nums[i + j] where:

0 <= j <= nums[i] and

i + j < n

Return the minimum number of jumps to reach nums[n - 1]. The test cases are generated such that you can reach nums[n - 1].

You are given an integer array prices where prices[i] is the price of a given stock on the ith day.

On each day, you may decide to buy and/or sell the stock. You can only hold at most one share of the stock at any time. However, you can buy it then immediately sell it on the same day.

Find and return the maximum profit you can achieve.

Given a string s, remove duplicate letters so that every letter appears once and only once. You must make sure your result is the smallest in lexicographical order among all possible results.

Given an integer array nums and an integer k, split nums into k non-empty subarrays such that the largest sum of any subarray is minimized.

Return the minimized largest sum of the split.

A subarray is a contiguous part of the array.

Given a positive integer n, return a string representing the smallest positive integer such that the product of its digits is equal to n, or "-1" if no such number exists.

You are given an integer n which is the length of a 0-indexed array nums, and a 0-indexed 2D-array ranges, which is a list of sub-ranges of nums (sub-ranges may overlap).

Each row ranges[i] has exactly 2 cells:

ranges[i][0], which shows the start of the ith range (inclusive)

ranges[i][1], which shows the end of the ith range (inclusive)

These ranges cover some cells of nums and leave some cells uncovered. Your task is to find all of the uncovered ranges with maximal length.

Return a 2D-array answer of the uncovered ranges, sorted by the starting point in ascending order.

By all of the uncovered ranges with maximal length, we mean satisfying two conditions:

Each uncovered cell should belong to exactly one sub-range

There should not exist two ranges (l1, r1) and (l2, r2) such that r1 + 1 = l2

Given a string s, partition s such that every substring of the partition is a palindrome.

Return the minimum cuts needed for a palindrome partitioning of s.

Given an integer array nums, return the length of the longest strictly increasing subsequence.

Given n non-negative integers representing an elevation map where the width of each bar is 1, compute how much water it can trap after raining.

A path in a binary tree is a sequence of nodes where each pair of adjacent nodes in the sequence has an edge connecting them. A node can only appear in the sequence at most once. Note that the path does not need to pass through the root.

The path sum of a path is the sum of the node's values in the path.

Given the root of a binary tree, return the maximum path sum of any non-empty path.

Given an input string s and a pattern p, implement regular expression matching with support for '.' and '*' where:

'.' Matches any single character.

'*' Matches zero or more of the preceding element.

The matching should cover the entire input string (not partial).