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You have written many programs to search mazes so matrix search shouldn’t be any different, or will it? The Problem: An integer matrix with RRR rows and CCC columns has (R2)(C2){R \choose 2}{C \choose 2}(2R​)(2C​) sub matrices. We want to select a sub matr

给你具有nnn个结点n−1n-1n−1条边的无向无环连通图，结点编号1∼n1 \sim n1∼n，每条边上有一个数作为他的边权，定义函数f(i,j)f(i,j)f(i,j)为连接i,ji,ji,j的简单路径的所有边权的异或值 求⨁i=1n⨁j=inf(i,j)\displaystyle \bigoplus_{i=1}^n \bigoplus_{j=i}^n f(i,j)i=1⨁n​j=i⨁n​f(i,j)，⊕\oplus⊕为按位异或运算，⨁i=lri\displaystyle \bigoplus_{i=l}