Algorithm 3 Exception handling algorithm
Input: all nodes' neighborhood N; error location permutation S'.
Output: node location permutation S.
1.	k = the number of S'; n = the actual node number
2.	delete the last element of S' in the Ns' (k−1)
3.	If Ns' (k−1) is null then
4.	break;
5.	else
6.	S' (k) = the first element of Ns' (k−1); delete S' (k − 1) in N
7.	end if
8.	while Ns' (k) is not empty do
9.	S'(k + 1) = the first element of Ns' (k−1)
10.	delete S' (k) in N
11.	k = k + 1
12.	end while
13.	k' = the number of the new ordering S'
14.	If k' = = n then
15.	S (1) = S' (n), use Algorithm 1 to derive the ordering S
16.	If S is the reversion of S' then
17.	S = S'
18.	else
19.	S = null
20.	end if
21.	else if n − k' = = 1 then
22.	turn to Algorithm 2
23.	else
24.	S = null
25.	end if