\documentclass[]{article}
\usepackage[T1]{fontenc}
\usepackage{polski}
\usepackage[utf8]{inputenc}
\usepackage[margin=1.25in]{geometry}
\usepackage{alltt}
\usepackage{titling}
\usepackage{pdfpages}
\usepackage{float}
\usepackage{amsmath}
\usepackage{booktabs}
\usepackage{tabularx}
\usepackage{amstext}
\usepackage{tikz}
\usepackage{xspace}
\usepackage{enumerate}
\usepackage{lmodern}
\usepackage{amsfonts}
\usepackage{amssymb}
\usepackage{mathtools}
\usepackage{alphalph}
\usepackage{algorithm}
\usepackage{algpseudocode}
\usepackage{wrapfig}
\usepackage[polish]{babel}
\usepackage{braket}
\usepackage{subcaption}

\DeclarePairedDelimiter\ceil{\lceil}{\rceil}
\DeclarePairedDelimiter\floor{\lfloor}{\rfloor}

\usetikzlibrary{decorations.pathmorphing, arrows.meta, positioning}
\usetikzlibrary{shapes.geometric, arrows}

\tikzstyle{problem} = [draw,outer sep=0,inner sep=5,minimum size=10]
\tikzstyle{solution} = [outer sep=0,inner sep=1,minimum size=10]
\tikzstyle{alpha} = [decorate, decoration={snake, amplitude=.5mm}, help lines]
\tikzstyle{max edge} = [very thick, blue]
\tikzstyle{vertex} = [draw, circle, thick]
\tikzstyle{small vertex} = [draw, circle, scale=.75]
\tikzstyle{weight} = [scale=.75, fill=white, draw]

\pgfdeclarelayer{background}
\pgfdeclarelayer{foreground}
\pgfsetlayers{background,main,foreground}

\renewcommand\leq\leqslant
\renewcommand\geq\geqslant

% opening
\title{PAA - Kolokwia, rozwiązania}
\author{Kacper Donat}

\newcounter{task}[section]
\newcounter{subtask}[task]
\newcounter{tip}[task]
\newcounter{note}[task]

\let\oldthetask\thetask
\let\oldthesubtask\thesubtask

\renewcommand{\thesubtask}{\alph{subtask}}
\renewcommand{\thetask}{\thesection.\oldthetask}
\renewcommand{\thetip}{\#\arabic{tip}}
\renewcommand{\thenote}{\#\arabic{note}}

\makeatletter
\newcommand{\note@nostar}[1]{\refstepcounter{note}\par\noindent\textbf{Uwaga \thenote:} #1\par}
\newcommand{\note@star}[1]{\par\noindent\textbf{Uwaga:} #1\par}
\newcommand{\note}{\@ifstar\note@star\note@nostar}

\newcommand{\tip@nostar}[1]{\refstepcounter{tip}\par\noindent\textit{Wskazówka \thetip:} #1\par}
\newcommand{\tip@star}[1]{\par\noindent\textit{Wskazówka:} #1\par}
\newcommand{\tip}{\@ifstar\tip@star\tip@nostar}
\makeatother

\newcommand{\NP}{\texttt{NP}\xspace}
\newcommand{\NPC}{\texttt{NPC}\xspace}
\newcommand{\NPI}{\texttt{NPI}\xspace}
\renewcommand{\P}{\texttt{P}\xspace}

\newcommand{\problem}[1]{{\tt #1}}

\newcommand{\taskend}{\par\vspace{.1cm}\hfill$\square$\vspace{.4cm}\par}
\newcommand{\task}{\vspace{.25cm}\refstepcounter{task} \noindent\par\texttt{Zadanie \thetask.\hspace{.25cm}}}
\newcommand{\subtask}[1][]{\refstepcounter{subtask}\par\noindent\hspace{.3cm}\thesubtask#1)\ }

\newcommand{\solution}{\par\vspace{.5cm}\noindent\textbf{Proponowane rozwiązanie:}\par}
\newcommand{\alphareduction}[2]{#1\ $\alpha$\ #2}

\newenvironment{shortcut}
    {\vspace{\baselineskip}\hbox{\textbf{Na skróty:}}\nointerlineskip\kern3pt\noindent\hrulefill\par\vspace{.5\baselineskip}}
    {\par\noindent\hrulefill\par\vspace{.5\baselineskip}}
\newenvironment{column}[1]{\noindent\begin{minipage}{#1\linewidth}}{\end{minipage}\vspace{.5\baselineskip}}

\floatname{algorithm}{Program}

% \setlength{\parskip}{.5em}

\begin{document}

\input{2013.01.26.tex}
\input{2011.01.18.tex}
\input{2018.bonus.tex}
\input{2018.01.25.tex}

\end{document}
