?uses System.Collections.Generic;

const
  MaxN = 1000;

type
  Point = class
  
  private 
    _index: integer;
    _previous: Point;
  
  public 
    constructor(index: integer);
    begin
      _index := index;
      _previous := nil;
    end;
    
    procedure SetPrevious(previous: Point);
    property Index: integer read _index;
    property Previous: Point read _previous;
  end;

procedure Point.SetPrevious(previous: Point);
begin
  _previous := previous;
end;

function BFS(startPoint: integer;
              targetPoint: integer; 
              params graph: Array[,] of integer): Point;
begin
  var queue: Queue<Point>;
  queue := new Queue<Point>;
  
  var isFound: boolean;
  isFound := false;
  
  var visited: Array[0..MaxN] of boolean;  
  queue.Enqueue(new Point(startPoint));
  
  while queue.Count <> 0 do
  begin
    var current: Point;
    current := queue.Dequeue();
    visited[current.Index] := true;
    
    if current.Index = targetPoint then
    begin
      isFound := true;
      result := current;
      break;
    end;
    
    for var i := 0 to Length(graph, 1) - 1 do
    begin
      if (graph[current.Index, i] = 1) and (not visited[i]) then
      begin
        var toAdd: Point;
        toAdd := new Point(i);
        toAdd.SetPrevious(current);
        queue.Enqueue(toAdd);
      end;
    end;
  end;
  if not isFound then
    result := nil;
end;

function DFS(startPoint: integer;
              targetPoint: integer; 
              params graph: Array[,] of integer): Point;
begin
  var stack: Stack<Point>;
  stack := new Stack<Point>;
  
  var isFound: boolean;
  isFound := false;
  
  var visited: Array[0..MaxN] of boolean;  
  stack.Push(new Point(startPoint));
  
  while stack.Count <> 0 do
  begin
    var current: Point;
    current := stack.Pop();
    visited[current.Index] := true;
    
    if current.Index = targetPoint then
    begin
      isFound := true;
      result := current;
      break;
    end;
    
    for var i := 0 to Length(graph, 1) - 1 do
    begin
      if (graph[current.Index, i] = 1) and (not visited[i]) then
      begin
        var toAdd: Point;
        toAdd := new Point(i);
        toAdd.SetPrevious(current);
        stack.Push(toAdd);
      end;
    end;
  end;
  if not isFound then
    result := nil;
end;

begin
  var graph: array[,] of integer;
  graph := new integer[10, 10];
  for var i := 0 to Length(graph, 0) - 1 do
    for var j := 0 to Length(graph, 1) - 1 do
      graph[i, j] := 0;
  var startPoint, targetPoint: integer;
  
  startPoint := 0;
  targetPoint := 5;
  Writeln(BFS(startPoint, targetPoint, graph));
  
  graph[0, 3] := 1;
  graph[3, 5] := 1;
  Writeln(DFS(startPoint, targetPoint, graph));
end.