蓝桥杯2016国赛---路径之谜

import java.util.*;

public class Main {
    static boolean[][] d;
    static int m, n, k;
    static int max = 0;
    static int sum = 0;
    static int sum1 = 0;
    static int[] a, b, r,w;
    static int[][] map;
    static boolean flag;
    static List lists = new ArrayList<>();
    public static void main(String[] args) {
        Scanner scanner = new Scanner(System.in);
        n = scanner.nextInt();
        k=0;
        map = new int[n][n];
        d = new boolean[n][n];
        a = new int[n];
        b = new int[n];
        r = new int[n];
        w = new int[n];
        r[0]=1;
        w[0]=1;
        for (int i = 0; i < n; i++)
            for (int j = 0; j < n; j++){
                map[i][j]=k;
                k++;
            }
        for (int i = 0; i < n; i++) {
            a[i] = scanner.nextInt();
        }
        for (int i = 0; i < n; i++) {
            b[i] = scanner.nextInt();
        }
        lists.add(0);
        d[0][0]=true;
        dfs(0,0);

    }
    public static void dfs(int i,int j) {
        if (flag)
            return;
        if (i == n - 1 && j == n - 1) {
            if (check()) {
                flag = true;
                System.out.print(lists.get(0));
                for (int l = 1; l < lists.size(); l++) {
                    System.out.print(" " + lists.get(l));
                }
            }
            return;
        }
        for (int k = 1; k <= 4; k++) {
            if (k == 1) {
                if (j + 1 < n && !d[i][j + 1]&&(r[i]+1<=b[i])&&(w[j+1]+1<=a[j+1])) {
                    d[i][j + 1] = true;
                    r[i]++;
                    w[j + 1]++;
                    lists.add(map[i][j + 1]);
                    dfs(i, j + 1);
                    d[i][j + 1] = false;
                    r[i]--;
                    w[j + 1]--;
                    lists.remove(lists.size() - 1);
                }
            }
            if (k == 2) {
                if (i + 1 < n && !d[i + 1][j]&&(r[i+1]+1<=b[i+1])&&(w[j]+1<=a[j])) {
                    d[i + 1][j] = true;
                    r[i + 1]++;
                    w[j]++;
                    lists.add(map[i + 1][j]);
                    dfs(i + 1, j);
                    d[i + 1][j] = false;
                    r[i + 1]--;
                    w[j]--;
                    lists.remove(lists.size() - 1);
                }
            }
            if (k == 3) {
                if (j - 1 >= 0 && !d[i][j - 1]&&(r[i]+1<=b[i])&&(w[j-1]+1<=a[j-1])) {
                    d[i][j - 1] = true;
                    r[i]++;
                    w[j - 1]++;
                    lists.add(map[i][j - 1]);
                    dfs(i, j - 1);
                    d[i][j - 1] = false;
                    r[i]--;
                    w[j - 1]--;
                    lists.remove(lists.size() - 1);
                }
            }
            if (k == 4) {
                if (i - 1 >= 0 && !d[i - 1][j]&&(r[i-1]+1<=b[i-1])&&(w[j]+1<=a[j])) {
                    d[i - 1][j] = true;
                    r[i - 1]++;
                    w[j]++;
                    lists.add(map[i - 1][j]);
                    dfs(i - 1, j);
                    d[i - 1][j] = false;
                    r[i - 1]--;
                    w[j]--;
                    lists.remove(lists.size() - 1);
                }
            }
        }
    }


    public static boolean check(){
        for(int i = 0;i