D.ml

let (n,p) = Scanf.scanf " %d %d" (fun a b -> (a, b));;

let m = Array.make_matrix n (n*n) 0;;
let flag = ref 0

let rec checkway m b c =
    if m.(b-1).(c-1) = 1 then flag := 1
    else
        for i = 0 to (n-1) do
            if m.(b-1).(i) = 1 then checkway m (b+1) c
        done;
    if flag = ref 0 then print_endline("NO")
    else print_endline("YES");

    for i = 0 to (p-1) do
      let (a,b,c) = Scanf.scanf " %s %d %d" (fun a b c -> (a, b, c)) in
      if a = "ADD" then m.(b-1).(c-1)<-1
      else if a = "DEL" then m.(b-1).(c-1)<-0
      else checkway m b c;
      Printf.printf "a=%s b=%d c=%d \n" a b c;
    done;

    let mm = Array.make_matrix n (n*n);;
    for i = 0 to (p-1) do


    for i = 0 to (n-1) do
      for j = 0 to (n-1) do
        print_int m.(i).(j)
      done;
      print_newline();
    done;