Substraightstring2.pas

//Do phuc tap O(n)
var
    fi,fo:text;
    k,i,j,n,dem,max:longint;
    a: array [1..1000000] of longint;
    mark: array [1..500000] of longint;//Truong hop xau nhat max = 2
begin
    assign(fi,'INPUT.INP');
    assign(fo,'OUTPUT.OUT');
    reset(fi);
    rewrite(fo);
    readln(fi,n);
    for i:=1 to n do
    read(fi,a[i]);
    i:=0;
    max:=0;
        while i<=(n-2) do
        begin
            inc(i);
            dem:=1;
            if (a[i] = a[i+1]) and (i < n) then //Tim truong hop thoa man
                while ( a[i] = a[i+1] ) and ( i<n ) do
                    begin
                        inc(i);
                        dem:=dem+1;
                    end;
            if dem>max then max:= dem;
        end;
    if max < 2 then //Max = 1 , Max=0 thi STOP
        begin
            write(fo,'KHONG TON TAI');
            close(fo);
            close(fi);
            exit;
        end;
    write(fo,Max);
    i:=0;
    j:=0;
    while i<=n-2 do
        begin
            inc(i);
            dem:=1;
            if (a[i] = a[i+1]) and (i < n) then
                while ( a[i] = a[i+1] ) and ( i<n ) do
                    begin
                        inc(i);
                        dem:=dem+1;
                    end;
            if dem=max then //Danh dau vi tri truong hop da thoa man
                begin
                inc(j);
                mark[j]:=i-max+1;
                end;
        end;
    writeln(fo);
    for k:=1 to j do
        begin
            for i:=mark[k] to mark[k]+max-1 do
                write(fo,a[i],' ');
            writeln(fo);
        end;
    close(fi);
    close(fo);
end.