图1-7是用14根火柴拼成的平房,要想把它变成楼房,请问至少需要移动几根火柴?
图1-7 P0HQiBwPKDDIzvAw1kHmZQ//Eu+vgPT/PAnFx13SnTBXSmpbEAZl7kD0qBGbgulw