Escape The Ghosts — LeetCode 789 Python Solution

The problem

You are playing a simplified PAC-MAN game on an infinite 2-D grid. You start at the point [0, 0], and you are given a destination point target = [xtarget, ytarget] that you are trying to get to.

Example

Input

ghosts = [[1,0],[0,3]], target = [0,1]

Output

true

Explanation

You can reach the destination (0, 1) after 1 turn, while the ghosts located at (1, 0) and (0, 3) cannot catch up with you.

Python solution

class Solution:
    def escapeGhosts(self, ghosts: List[List[int]], target: List[int]) -> bool:
        tx, ty = target
        return all(abs(tx - x) + abs(ty - y) > abs(tx) + abs(ty) for x, y in ghosts)

Complexity

Pattern: Math and Number Theory

Find the closed form, the invariant, or the modular identity — and skip the loop entirely. LeetCode 789. Escape The Ghosts is filed here on both counts: the reference solution below belongs to the algorithm family this hub collects, and LeetCode tags it Math.

The math and number theory guide has the Python template for the pattern and the 485 LeetCode problems that use it.

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