program ValidParentheses;
function StringContainsValidParentheses(s: string): Boolean;
var
arr: array of Char; // Dynamic array to simulate a stack
ch: Char;
top: Integer;
begin
SetLength(arr, 0); // Initialize the stack
top := -1; // Represents the top of the stack (empty)
for ch in s do
begin
if ch = '(' then
begin
Inc(top); // Move the stack pointer up
SetLength(arr, top + 1);
arr[top] := ')';
end
else if ch = '{' then
begin
Inc(top);
SetLength(arr, top + 1);
arr[top] := '}';
end
else if ch = '[' then
begin
Inc(top);
SetLength(arr, top + 1);
arr[top] := ']';
end
else if (top < 0) or (arr[top] <> ch) then
begin
Exit(False); // Return False if the stack is empty or mismatched
end
else
begin
Dec(top); // Pop the stack
end;
end;
// If the stack is empty at the end, the parentheses are valid
StringContainsValidParentheses := (top = -1);
end;
begin
WriteLn(StringContainsValidParentheses('(){}[]'));
WriteLn(StringContainsValidParentheses('([{}])'));
WriteLn(StringContainsValidParentheses('(){}[]()(){}'));
WriteLn(StringContainsValidParentheses('(]'));
WriteLn(StringContainsValidParentheses('({[)]}'));
end.
(*
run:
TRUE
TRUE
TRUE
FALSE
FALSE
*)
