spoj#SPECIALG. Special Graph
Special Graph
本题没有可用的提交语言。
You are given a directed graph with N vertices. The special thing about the graph is that each vertex has at most one outgoing edge. Your task is to answer the following two types of queries
1 a delete the only edge outgoing from vertex a. It is guaranteed that the edge exists. 1<= a<= N
2 a b output the length of the shortest path from vertex a to vertex b, if the path exists. Otherwise
output "-1" without quotes. 1<=a, b<= N
Input
First line of input contains a natural number N<=10^5 the number of vertices in the graph.
The following line contains N integer numbers, i-th number is next[i] (0<= next[i]<= N), meaning that there
is an edge from vertex i to vertex next[i]. If next[i] = 0, assume that there is no outgoing edge from vertex
i.
Third line contains a natural number M<=10^5 the number of queries.
The following M lines contain a query each. Queries are given in the manner described above.
Output
On the i-th line output the answer for the i-th query of type 2 a b.
Example
Input: 6 3 3 4 5 6 4 6 2 1 6 2 1 4 2 1 2 1 3 2 1 6 2 1 4</p>Output: 4 2 -1 -1 -1