寻找 \(\lambda(x, y)\) 使得：
\[\begin{align*} b^*_i &= \bigoplus\limits_{j \subseteq i}{\lambda(i, j)\&B_j}\\ &= \bigoplus\limits_{j \subseteq i}{\left[\lambda(i, j)\&\bigoplus\limits_{t\subseteq u-j, t\in[0,n)}{b_t}\right]}\\ &= \bigoplus\limits_{t \in [0,n)}{\left[b_t\&\bigoplus\limits_{j\subseteq i-(i\&t)}{\lambda(i, j)}\right]}\\ &= \bigoplus\limits_{t\in[0,n), i\subseteq t}{b_i} \end{align*} \]则使得：
\[\begin{aligned} &\bigoplus\limits_{j\subseteq i-(i\&t)}{\lambda(i, j)} = [i\subseteq t]u\\ \iff &\bigoplus\limits_{j\subseteq x}{\lambda(i, j)} = [x = 0]u\\ \iff &\lambda(i,j) = u \end{aligned} \]则：
\[b^*_i = \bigoplus\limits_{j \subseteq i}{B_j} = \bigoplus\limits_{t\in[0,n), i\subseteq t}{b_i} \] 标签：begin,right,Lost,limits,CF1713F,bigoplus,Array,subseteq,lambda From： https://www.cnblogs.com/kyeecccccc/p/16970081.html