Matrix: Best Meeting Point - mbhushan/codique GitHub Wiki

Best Meeting Point

A group of two or more people wants to meet and minimize the total travel distance. You are given a 2D grid of values 0 or 1, where each 1 marks the home of someone in the group. The distance is calculated using Manhattan Distance, where distance(p1, p2) = |p2.x - p1.x| + |p2.y - p1.y|.

For example, given three people living at (0,0), (0,4), and (2,2):

1 - 0 - 0 - 0 - 1

0 - 0 - 0 - 0 - 0

0 - 0 - 1 - 0 - 0

The point (0,2) is an ideal meeting point, as the total travel distance of 2+2+2=6 is minimal. So return 6.

High Level Solution:

Find the x and y coordinates of all people in the group and get the x-axis median and y-axis median say a & b respectively. Now get the manhattan distance from each person (Xi, Yi) to (a,b) points, which will be the required min distance.

  • Time Complexity: O(n^2)
  • Space Complexity: O(n^2)

Working Solution:

BestMeetingPoint.java

Send me a pull request if you feel this solution can be improved further.