Task: Sokoban


C++: #include <iostream>
#include <string>
#include <vector>
#include <queue>
#include <regex>
#include <tuple>
#include <set>
#include <array>
using namespace std;

class Board
{
public:
  vector<vector<char>> sData, dData;
  int px, py;

  Board(string b)
  {
    regex pattern("([^\\n]+)\\n?");
    sregex_iterator end, iter(b.begin(), b.end(), pattern);
    
    int w = 0;
    vector<string> data;
    for(; iter != end; ++iter){
      data.push_back((*iter)[1]);
      w = max(w, (*iter)[1].length());
    }

    for(int v = 0; v < data.size(); ++v){
      vector<char> sTemp, dTemp;
      for(int u = 0; u < w; ++u){
        if(u > data[v].size()){
          sTemp.push_back(' ');
          dTemp.push_back(' ');
        }else{
          char s = ' ', d = ' ', c = data[v][u];

          if(c == '#')
            s = '#';
          else if(c == '.' || c == '*' || c == '+')
            s = '.';

          if(c == '@' || c == '+'){
            d = '@';
            px = u;
            py = v;
          }else if(c == '$' || c == '*')
            d = '*';

          sTemp.push_back(s);
          dTemp.push_back(d);
        }
      }

      sData.push_back(sTemp);
      dData.push_back(dTemp);
    }
  }

  bool move(int x, int y, int dx, int dy, vector<vector<char>> &data)
  {
    if(sData[y+dy][x+dx] == '#' || data[y+dy][x+dx] != ' ') 
      return false;

    data[y][x] = ' ';
    data[y+dy][x+dx] = '@';

    return true;
  }

  bool push(int x, int y, int dx, int dy, vector<vector<char>> &data)
  {
    if(sData[y+2*dy][x+2*dx] == '#' || data[y+2*dy][x+2*dx] != ' ')
      return false;

    data[y][x] = ' ';
    data[y+dy][x+dx] = '@';
    data[y+2*dy][x+2*dx] = '*';

    return true;
  }

  bool isSolved(const vector<vector<char>> &data)
  {
    for(int v = 0; v < data.size(); ++v)
      for(int u = 0; u < data[v].size(); ++u)
        if((sData[v][u] == '.') ^ (data[v][u] == '*'))
          return false;
    return true;
  }

  string solve()
  {
    set<vector<vector<char>>> visited;
    queue<tuple<vector<vector<char>>, string, int, int>> open;

    open.push(make_tuple(dData, "", px, py));
    visited.insert(dData);

    array<tuple<int, int, char, char>, 4> dirs;
    dirs[0] = make_tuple(0, -1, 'u', 'U');
    dirs[1] = make_tuple(1, 0, 'r', 'R');
    dirs[2] = make_tuple(0, 1, 'd', 'D');
    dirs[3] = make_tuple(-1, 0, 'l', 'L');

    while(open.size() > 0){
      vector<vector<char>> temp, cur = get<0>(open.front());
      string cSol = get<1>(open.front());
      int x = get<2>(open.front());
      int y = get<3>(open.front());
      open.pop();

      for(int i = 0; i < 4; ++i){
        temp = cur;
        int dx = get<0>(dirs[i]);
        int dy = get<1>(dirs[i]);

        if(temp[y+dy][x+dx] == '*'){
          if(push(x, y, dx, dy, temp) && (visited.find(temp) == visited.end())){
            if(isSolved(temp))
              return cSol + get<3>(dirs[i]);
            open.push(make_tuple(temp, cSol + get<3>(dirs[i]), x+dx, y+dy));
            visited.insert(temp);
          }
        }else if(move(x, y, dx, dy, temp) && (visited.find(temp) == visited.end())){
          if(isSolved(temp))
            return cSol + get<2>(dirs[i]);
          open.push(make_tuple(temp, cSol + get<2>(dirs[i]), x+dx, y+dy));
          visited.insert(temp);
        }
      }
    }

    return "No solution";
  }
};

int main()
{
  string level =
    "#######\n"
    "#     #\n"
    "#     #\n"
    "#. #  #\n"
    "#. $$ #\n"
    "#.$$  #\n"
    "#.#  @#\n"
    "#######";

  Board b(level);

  cout << level << endl << endl << b.solve() << endl;
  return 0;
}




Java: import java.util.*;

public class Sokoban {
    String destBoard, currBoard;
    int playerX, playerY, nCols;

    Sokoban(String[] board) {
        nCols = board[0].length();
        StringBuilder destBuf = new StringBuilder();
        StringBuilder currBuf = new StringBuilder();

        for (int r = 0; r < board.length; r++) {
            for (int c = 0; c < nCols; c++) {

                char ch = board[r].charAt(c);

                destBuf.append(ch != '$' && ch != '@' ? ch : ' ');
                currBuf.append(ch != '.' ? ch : ' ');

                if (ch == '@') {
                    this.playerX = c;
                    this.playerY = r;
                }
            }
        }
        destBoard = destBuf.toString();
        currBoard = currBuf.toString();
    }

    String move(int x, int y, int dx, int dy, String trialBoard) {

        int newPlayerPos = (y + dy) * nCols + x + dx;

        if (trialBoard.charAt(newPlayerPos) != ' ')
            return null;

        char[] trial = trialBoard.toCharArray();
        trial[y * nCols + x] = ' ';
        trial[newPlayerPos] = '@';

        return new String(trial);
    }

    String push(int x, int y, int dx, int dy, String trialBoard) {

        int newBoxPos = (y + 2 * dy) * nCols + x + 2 * dx;

        if (trialBoard.charAt(newBoxPos) != ' ')
            return null;

        char[] trial = trialBoard.toCharArray();
        trial[y * nCols + x] = ' ';
        trial[(y + dy) * nCols + x + dx] = '@';
        trial[newBoxPos] = '$';

        return new String(trial);
    }

    boolean isSolved(String trialBoard) {
        for (int i = 0; i < trialBoard.length(); i++)
            if ((destBoard.charAt(i) == '.')
                    != (trialBoard.charAt(i) == '$'))
                return false;
        return true;
    }

    String solve() {
        class Board {
            String cur, sol;
            int x, y;

            Board(String s1, String s2, int px, int py) {
                cur = s1;
                sol = s2;
                x = px;
                y = py;
            }
        }
        char[][] dirLabels = {{'u', 'U'}, {'r', 'R'}, {'d', 'D'}, {'l', 'L'}};
        int[][] dirs = {{0, -1}, {1, 0}, {0, 1}, {-1, 0}};

        Set<String> history = new HashSet<>();
        LinkedList<Board> open = new LinkedList<>();

        history.add(currBoard);
        open.add(new Board(currBoard, "", playerX, playerY));

        while (!open.isEmpty()) {
            Board item = open.poll();
            String cur = item.cur;
            String sol = item.sol;
            int x = item.x;
            int y = item.y;

            for (int i = 0; i < dirs.length; i++) {
                String trial = cur;
                int dx = dirs[i][0];
                int dy = dirs[i][1];

                
                if (trial.charAt((y + dy) * nCols + x + dx) == '$') {

                    
                    if ((trial = push(x, y, dx, dy, trial)) != null) {

                        
                        if (!history.contains(trial)) {

                            String newSol = sol + dirLabels[i][1];

                            if (isSolved(trial))
                                return newSol;

                            open.add(new Board(trial, newSol, x + dx, y + dy));
                            history.add(trial);
                        }
                    }

                
                } else if ((trial = move(x, y, dx, dy, trial)) != null) {

                    if (!history.contains(trial)) {
                        String newSol = sol + dirLabels[i][0];
                        open.add(new Board(trial, newSol, x + dx, y + dy));
                        history.add(trial);
                    }
                }
            }
        }
        return "No solution";
    }

    public static void main(String[] a) {
        String level = "#######,#     #,#     #,#. #  #,#. $$ #,"
                + "#.$$  #,#.#  @#,#######";
        System.out.println(new Sokoban(level.split(",")).solve());
    }
}