自底向上计算 The heart of the algorithm is the following procedure,which,given matrices L()and W,returns the matrix L(m).That is,it extends the shortest paths com- puted so far by one more edge. EXTEND-SHORTEST-PATHS(L,W) 1 n L.rows 2 let L'= (be a new nx nmatrix 问题4： 3 for i=1 to n 4 for j 1to n 5 号=∞ one more 6 for k 1to n 7 号=min(5,lk+0对) edge”体现在 8 return L' 哪里？自底向上计算