I have an idea to make the duck survive:

1. the fox is chasing the duck and always goes in the direction that is closer to the duck
2. the duck is more mobile than the fox; the duck can move anywhere in the lake, but the fox is limited to the circular shore



This is a very simplified rendition of what the duck should do. The premise is that the duck moves in the direction opposite the fox, and that it can make very quick angle shifts. Since the fox always moves as close to the duck as possible, if the duck zigzags in an angle that is close to horizontal, it is able to gradually move toward the opposite edge, while the fox moves back and forth in an arc. The zigzags should initally be short, but should be longer as the duck moves further from the fox, since the longer distance reduces the angle between the duck, the fox, and the diameter, and so the duck's angle shifts have a less pronounced effect. When the duck has moved about 30-35% of the way down its radius, it can swim directly toward the shore; the fox will be unable to catch up, since it has been stuck at the other end.

所有跟帖： 

• no -guest007- ♀ (524 bytes) () 05/15/2010 postreply 21:58:07

• 真不油墨，逗狐狸來回跑多好玩，哈哈。 -AnaZhang- ♀ (170 bytes) () 05/17/2010 postreply 14:45:26