breadth-first-search.txt

:: init_node, (v) => {:: val, [v] 
                      :: color, 0
                      :: d, 99999999
                      :: pi, [0]}

:: init_graph, () => {:: V, {}
                      :: Adj, {}}

:: bfs, (G, s) => {set([s], color, 1)
                   set([s], d, 0)
                   set([s], pi, [0])
                   :: Q, {}
                   add([Q], [s])
                   | ~((size([Q]) == 0)) : () => {:: u, remove([Q], 1)
                						      | [G][Adj][[u][val]] : (v) => (([v][color] == 0) ? {set([v], color, 1)
                                                                                 			      set([v], d, ([u][d] + 1))  
                                                                                 			      set([v], pi, [u])
                                                                                                  add([Q], [v])})|
                                              set([u], color, 2)}|}

::n, read()
::G, [init_graph]()
| [n] : (i) => {add([G][V], [init_node]([i]))
                add([G][Adj], {})}|

::in1, (read() + 1)
| ~(([in1] == 0)) : () => {::in2, (read() + 1)
                       	   add([G][Adj][[in1]], [G][V][[in2]])
                           add([G][Adj][[in2]], [G][V][[in1]])
                           ((read() + 1) -> in1)}|

::u, (read() + 1)
::v, (read() + 1)

([G][V][[u]] -> u)
([G][V][[v]] -> v)

[bfs]([G], [u])

(([v][pi] == [0]) ? write(-1) : {::ptr, [v]
								 ::stack, {}
								 | ~(([ptr] == [0])) : () => {add([stack], [ptr])
                                                 			  ([ptr][pi] -> ptr)}|
                                 | size([stack]), 1 : (i) => {write(([stack][[i]][val] - 1)) newline()}|})