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.
You are given a grid of size m x n where each cell is either land (1) or sea (0). Your task is to determine the number of land cells that are completely enclosed by sea cells. A land cell is considered enclosed if it cannot reach the boundary of the grid via other land cells.
You are given two strings, s1 and s2, which contain the same length, and a third string baseStr. Each pair of corresponding characters from s1 and s2 represent equivalent characters. Your task is to return the lexicographically smallest equivalent string for baseStr, where each character is replaced with its lexicographically smallest equivalent based on the equivalency information from s1 and s2.
You are given a string s and an array of pairs of indices pairs where each pair pairs[i] = [a, b] represents two indices in the string. You can swap the characters at any of these index pairs any number of times. Your task is to return the lexicographically smallest string that can be obtained after performing the swaps.
You are given a 2D grid with 0s (land) and 1s (water). An island is a group of 0s connected 4-directionally, and a closed island is a group of 0s completely surrounded by 1s. Your task is to count how many closed islands are present in the grid.
You are given a 2D grid where each cell is either 1 (indicating a server) or 0 (no server). Two servers are said to communicate if they are in the same row or column. The task is to find the number of servers that can communicate with at least one other server.