Sixth, the traversal of the tree
1. Required sequence in pre-sequence
Procedure Solve (Pre, Mid: String);
VAR i: integer;
Begin
IF (pre= ') or (MID =' ') THEN EXIT;
I: = POS (Pre [1], MID);
Solve (Copy (Pre, 2, I), COPY (MID, 1, I-1);
Solve (Copy (Pre, I 1, Length (Pre) -i), Copy (MID, I 1, Length (MID) -i));
Post: = post pre [1]; {plus root, post-recursive end traversal traversal}
END;
2. Present sequence prequet sequence
Procedure Solve (MID, Post: String);
VAR i: integer;
Begin
IF (MID = '') or (post = '') THEN EXIT;
I: = POS (Post [Length (POST)], MID);
Pre: = pre post [length (post)]; {plus root, after recursive end, pre-sequence traversal}
Solve (Copy (MID, 1, I-1), COPY (POST, 1, I-1);
Solve (Copy (MID, I 1, Length (MID) -i), Copy (POST, I, Length (POST) -i);
END;
3. One of known pre-sequences
Function OK (S1, S2: String): Boolean;
Var i, l: integer; p: boolean;
Begin
OK: = true;
L: = Length (S1);
For i: = 1 to l do begin
P: = false;
For j: = 1 to l do
IF S1 [I] = S2 [J] THEN P: = TRUE
IF NOT; End;
END;
END;
Procedure Solve (Pre, Post: String);
VAR i: integer;
Begin
IF (pre = '') or (post = '') THEN EXIT;
I: = 0;
Repeat
INC (I);
Until OK (Copy (Pre, 2, I), Copy (POST, 1, I));
Solve (Copy (Pre, 2, I), COPY (POST, 1, I));
Midstr: = Midstr pre [1];
Solve (Copy (Pre, I 2, Length (Pre) -i-1), Copy (POST, I 1, Length (POST) -i-1);
END;
