prolog 找路例子程序：
=== === === === === ===
Part 1-Adding connections
Part 2-Simple Path
example
| ?- path1(a,b,P,T).
will produce the response:
T = 15
P = [a,b] ?
Part 3 - Non-repeating path
As an example, the query:
?- path2(a,h,P,T).
will succeed and may produce the bindings:
P = [a,depot,b,d,e,f,h]
T = 155
Part 4 - Generating a path below a cost threshold
As an example, the query:
?- path_below_cost(a,[a,b,c,d,e,f,g,h],RS,300).
returns:
RS = [a,b,depot,c,d,e,g,f,h] ?
RS = [a,c,depot,b,d,e,g,f,h] ?
no
==================================
計算這個智力題：
在這個乘法算式里，每一個字母代表著0-9中的一個數，不同字母代表不同數。
A B C D E F G H
* A J
---------------------
E J A H F D G K C
B D F H A J E C
---------------------
C C C C C C C C C
請問，C 代表哪個數字？
