You are in a building with multiple rooms, each containing a set of keys to unlock other rooms. Initially, only the first room (room 0) is unlocked. You are tasked with determining whether you can visit all the rooms, starting from room 0. To enter a locked room, you must have its corresponding key, which can only be obtained by visiting other rooms.
You are given a group of n people, each with a unique amount of money and quietness. An array richer specifies the relationships between people where richer[i] = [ai, bi] indicates that person ai has more money than person bi. You are also given an array quiet where quiet[i] represents the quietness of person i. Your task is to return an array answer where answer[x] is the person y who has the least quietness among all people who have equal or more money than person x.
You are given a group of n people, labeled from 1 to n. Each person may dislike other people, and they should not be placed in the same group. Your task is to determine if it is possible to split the group of people into two subgroups, such that no one in the same group dislikes each other. Each pair of dislikes is represented by an array of two people who cannot be in the same group. Return true if such a split is possible, otherwise return false.
You are given a set of stones placed on a 2D plane at various integer coordinate points. A stone can be removed if it shares the same row or column as another stone that has not been removed yet. Your task is to determine the maximum number of stones that can be removed from the plane by performing valid operations.
You are given a list of equations where each equation represents a relationship between two variables in the form ‘xi==yi’ or ‘xi!=yi’. Determine if it’s possible to assign integer values to variables such that all equations are satisfied.
In a town with n people, one person may be the judge. The judge trusts no one and is trusted by everyone else. Given a list of trust relationships, identify the town judge or return -1 if no judge exists.