isFenced

import java.util.ArrayList;
class Main {
    public static void main(String[] args) {
        show(getNeighbours(4, 2));

        checkIsFenced(4, "a11c10d17a30b18c5d6a29b31c16d12", "a11");
        checkIsFenced(4, "c1c5d6c10a11d12c16d17b18d19b22b23a24a29a30b31", "d17");
        checkIsNotFenced(4, "c1c5d6c10a11d12c16d17b18d19b22b23a24a29a30b31", "c1c5c10c16");
        checkIsNotFenced(4, "c1c5d6c10a11d12c16d17b18d19b22b23a24a29a30b31", "b18");
        checkIsNotFenced(4, "c1c5d6c10a11d12c16d17b18d19b22b23a24a29a30b31", "a24a29a30");
        checkIsFenced(4, "c5d6c10d12c16d17b18b19c22b26c28a29a30b31a33d34a35", "d34");
        checkIsNotFenced(4, "c5d6c10d12c16d17b18b19c22b26c28a29a30b31a33d34a35", "a29a30a33a35");
        checkIsNotFenced(4, "c5d6c10d12c16d17b18b19c22b26c28a29a30b31a33d34a35", "d17");
        
        checkIsFenced(5, "a20c22d14a13b21c30d15a28b29c38d7a12b23c31d16a36b32c40d24a46b39c41d6a48b47c37d33", "b21b29");
        checkIsFenced(5, "a20c22d14a13b21c30d15a28b29c38d7a12b23c31d16a36b32c40d24a46b39c41d6a48b47c37d33", "b23b32");
        
        checkIsNotFenced(5, "a11d12d13c18a19c20a26b27b28", "c20");
        checkIsNotFenced(5, "a20c22d14a13b21c30d15a28b29c38d7a12b23c31d16a36b32c40d24a46b39c41d6a48b47c37d33", "a12a13a20a28a36");
        checkIsFenced(5, "a11d12d13c18a19c20a26b27b28", "c18");
        
        checkIsFenced(5, "d0a5a6d11a12d18c19a20b26c27b28c35b36", "d11d18");
        
        checkIsNotFenced(5, "a11d12d13c18a19c20a26b27b28", "c20");
        checkIsNotFenced(5, "a11d12d13c18a19c20a26b27b28", "a11a19");
        checkIsNotFenced(5, "d0a5a6d11a12d18c19a20b26c27b28c35b36", "c19c27c35");
        checkIsNotFenced(5, "d0a5a6d11a12d18c19a20b26c27b28c35b36", "a5a6a12a20");
    }
    static void checkIsFenced(int l, String board, String bloom) {
        if (!isFenced(l, board, bloom)) {
            System.out.printf("should true: %d %s %s\n", l, board, bloom);
        }
    }
    static void checkIsNotFenced(int l, String board, String bloom) {
        if (isFenced(l, board, bloom)) {
            System.out.printf("should false: %d %s %s\n", l, board, bloom);
        }
    }
    static boolean isFenced(int l, String board, String bloom) {
        String[] nsa = board.split("[a-d]");
        String[] csa = board.split("\\d+");
        ArrayList<String> cs = new ArrayList<String>();
        ArrayList<Integer> ns = new ArrayList<Integer>();
        for (int i = 0; i < csa.length; ++i) {
            cs.add(csa[i]);
            ns.add(Integer.parseInt(nsa[i + 1]));
        }
        String bc = bloom.substring(0, 1);
        String[] bna = bloom.split("[a-d]");
        ArrayList<Integer> bns = new ArrayList<Integer>();
        for (int i = 1; i < bna.length; ++i) {
            bns.add(Integer.parseInt(bna[i]));
        }
        // build map
        int[][] map = new int[l * 2 - 1][l * 2 - 1];
        String[][] cmap = new String[l * 2 - 1][l * 2 - 1];
        int s = 0, e = l, c = 0, i = 0, j = 0;
        for (i = 0; i < l * 2 - 1; ++i) {
            for (j = 0; j < l * 2 - 1; ++j) {
                cmap[i][j] = ".";
                if (j < s || j >= e) {
                    cmap[i][j] = "e";
                    map[i][j] = -1;
                } else {
                    map[i][j] = c++;
                    if (ns.contains(map[i][j])) {
                        String x = cs.get(ns.indexOf(map[i][j]));
                        if (!x.equals(bc) || bns.contains(map[i][j])) {
                            cmap[i][j] = x;
                        }
                    }
                }
            }
            if (i < l - 1) e++;
            if (i >= l - 1) s++;
        }
        // for (i = 0; i < l * 2 - 1; ++i) {
        //     show(cmap[i]);
        // }
        ns.clear();
        for (int _i : bns) {
            int[] neighbours = getNeighbours(l, _i);
            for (int _j : neighbours) {
                if (ns.contains(_j)) continue;
                ns.add(_j);
            }
        }
        // show(ns);
        boolean b = true;
        for (i = 0; i < l * 2 - 1; ++i) {
            for (j = 0; j < l * 2 - 1; ++j) {
                if (ns.contains(map[i][j]) && !bns.contains(map[i][j])) {
                    // System.out.printf("(%d, %d) %s\n", i, j, cmap[i][j]);
                    if (cmap[i][j].equals(bc) || cmap[i][j].equals(".")) {
                        b = false;
                        break;
                    }
                }
            }
            if (!b) break;
        }
        return b;
    }
    public static int[] getNeighbours(int l, int n) {
        // FIXME Task 4: get the list of spaces which are neighbours to the given space
        // only work for size of 4,need to fix
        if (l <= 1) return new int[0];
        int[][] map = new int[l * 2 - 1][l * 2 - 1];
        int s = 0, e = l, c = 0, _i = -l, _j = -l, i = 0, j = 0;
        for (i = 0; i < l * 2 - 1; ++i) {
            for (j = 0; j < l * 2 - 1; ++j) {
                if (j < s || j >= e) {
                    map[i][j] = -1;
                } else {
                    if ((map[i][j] = c++) == n) {
                        _i = i; _j = j;
                    }
                }
            }
            if (i < l - 1) e++;
            if (i >= l - 1) s++;
        }
        ArrayList<Integer> a = new ArrayList<Integer>();
        i = _i; j = _j;
        for (_i = -1; _i <= 1; ++_i) {
            for (_j = -1; _j <= 1; ++_j) {
                if (_i + _j == 0) continue;
                s = i + _i; e = j + _j;
                if (0 <= s && s < l * 2 - 1 && 0 <= e && e < l * 2 - 1) {
                    if (map[s][e] >= 0) {
                        a.add(map[s][e]);
                    }
                }
            }
        }
        int[] b = new int[a.size()];
        for (i = 0; i < a.size(); ++i)
            b[i] = a.get(i);
        return b;
    }
    static void show(String[] arr) {
        System.out.print(arr.length);
        for (String s : arr) {
            System.out.print(" [" + s + "]");
        }
        System.out.println();
    }
    static void show(int[] arr) {
        System.out.print(arr.length);
        for (int s : arr) {
            System.out.print(" [" + s + "]");
        }
        System.out.println();
    }
    static void show(ArrayList<Integer> arr) {
        System.out.print(arr.size());
        for (int s : arr) {
            System.out.print(" [" + s + "]");
        }
        System.out.println();
    }
}