#arc121f. [arc121_f]Logical Operations on Tree

[arc121_f]Logical Operations on Tree

给定一棵树,给每个点填 0011,给每条边填 AND\text{AND}OR\text{OR},在所有 2n+n12^{n+n-1} 种填法中,计数有多少种满足存在一种缩边的顺序,使得每次把一条边的两个端点缩成一个点,权为原端点与边的运算值,最终点的权为 11