Добавил:
Studfiles2
Опубликованный материал нарушает ваши авторские права? Сообщите нам.
Вуз:
Предмет:
Файл:Алгоритмы на графах / dfs / prepost
.pas{ graphs by boris }
{ depth-first search (pre and post order) }
const
maxn = 250;
var
a: array [1..maxn, 1..maxn] of boolean;
pre, post: array [1..maxn] of word;
pre_c, post_c, n: longint;
procedure init;
var
i, x, y, nn: longint;
begin
fillchar(a, sizeof(a), false);
fillchar(pre, sizeof(pre), 0);
fillchar(post, sizeof(post), 0);
pre_c := 1;
post_c := 1;
assign(input, 'graph.in');
reset(input);
read(n);
read(nn);
for i := 1 to nn do
begin
read(x, y);
a[x, y] := true;
a[y, x] := true; { Ґб«Ё Ґ®аЁҐвЁа®ў л© Ја д }
end;
end;
procedure print;
var
i, j: integer;
begin
writeln;
writeln('number of vertex : ', n);
writeln('adjacency matrix');
for i := 1 to n do
begin
for j := 1 to n do
write(ord(a[i, j]));
writeln;
end;
end;
procedure dfs(v: longint);
var
i: integer;
begin
pre[v] := pre_c;
inc(pre_c);
for i := 1 to n do
if (pre[i] = 0) and a[v, i] then
dfs(i);
post[v] := post_c;
inc(post_c);
end;
var
i: longint;
begin
init;
writeln('depth-first search (pre and post order)');
for i := 1 to n do
if pre[i] = 0 then
dfs(i);
write('pre order : ');
for i := 1 to n do
write(pre[i], ' ');
writeln;
write('post order : ');
for i := 1 to n do
write(post[i], ' ');
print;
end.