Insight · ★★★☆☆ · ~6 min
Dead Men Walking (Zombie Collisions)
Zombies walk a line and reverse on collision. Count total collisions.
by MindYourPuzzle
100 zombies on a line, 1 unit apart. Each moves at the same speed: some left, some right. When two zombies collide, they reverse direction.
Given their initial directions, how many total collisions occur?
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