Ant's travel in a grid | PROGRAMMING INTERVIEWS

Ant's travel in a grid | PROGRAMMING INTERVIEWS

Question: There is an ant which can walk around on a planar grid. The ant can move one space at a time left, right, up or down. That is, from (x, y) the ant can go to (x+1, y), (x-1, y), (x, y+1), and (x, y-1). Points where the sum of the digits of the x coordinate plus the sum of the digits of the y coordinate are greater than 25 are inaccessible to the ant. For example, the point (59, 79) is inaccessible because 5 + 9 + 7 + 9 = 30, which is greater than 25. How many points can the ant access if it starts at (1000, 1000), including (1000, 1000) itself?

Read full article from Ant's travel in a grid | PROGRAMMING INTERVIEWS