abcnow

三个红色和两个黑色tvb now,tvbnow,bttvb! }, n* h+ v! Q' \2 o3 F  i0 c# l8 u
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最后那个说我不知道我戴什么颜色帽子.
+ v0 d4 }- t0 C% ^. h& c+ g- the front #1 , #2 must not be black/black.  Otherwise, #3 will know he is red.  #1/#2 must be red/red or red/black or black/red.
0 n; K% u, a  o$ ttvb now,tvbnow,bttvbtvb now,tvbnow,bttvb4 R1 W( @8 I2 p6 i/ g
中间那个说我也不知道我戴什么颜色帽子.tvb now,tvbnow,bttvb& u% h2 t4 V5 |4 ~$ a
- for #2, if he see #1 wearing black, he can be sure he is red.  since #2 cannot be sure, then #1 must NOT be wearing black.4 i3 o' V( A. |1 A# t3 f- q9 j# z

$ e) c+ T! B9 I9 }2 \# vtvb now,tvbnow,bttvb但是第一个说我知道我戴什么颜色帽子.1 c9 B1 N6 G1 f% y4 A/ s2 e# b
- #1 must be wearing RED