# coding=utf-8 id = 135 name = 'memberBT/2' slug = 'find elements in a binary tree' description = '''\ <p><code>memberBT(X, T)</code>: <code>X</code> is an element of the binary tree <code>T</code>. A binary tree node is represented with the structure <code>b(L, E, R)</code>, where <code>L</code> and <code>R</code> are left and right subtrees, respectively, and <code>E</code> is the node's value. An empty tree is denoted by <code>nil</code>.</p> <pre> ?- memberBT(X, b(b(nil,2,nil),1,b(nil,3,nil))). X = 1 ; X = 2 ; X = 3. </pre>''' hint = {}