给定一棵树
(0,1)
(0,7)
(0,12)
(0,13)
(0,15)
(1,2)
(1,4)
(1,6)
(1,7)
(2,3)
(2,5)
(2,6)
(3,4)
(3,5)
(7,8)
(8,9)
(8,10)
(8,11)
(9,10)
(9,11)
(12,13)
(13,14)
(13,15)
0代表根节点,每一数组代表两节点间有无向边。请问,如何判断某节点是否是另一节点的祖先?谢谢
(0,1)
(0,7)
(0,12)
(0,13)
(0,15)
(1,2)
(1,4)
(1,6)
(1,7)
(2,3)
(2,5)
(2,6)
(3,4)
(3,5)
(7,8)
(8,9)
(8,10)
(8,11)
(9,10)
(9,11)
(12,13)
(13,14)
(13,15)
0代表根节点,每一数组代表两节点间有无向边。请问,如何判断某节点是否是另一节点的祖先?谢谢
// judge if a is ancestor of b.
// travel from b to 0
// return if a is visted
}