第一题、模拟涂色游戏

import java.util.*;
public class Main { 

    public static void main(String[] args) { 
        Scanner sc = new Scanner(System.in);
        String inHand = sc.nextLine();
        String toPrint = sc.nextLine();
        if(inHand==null || inHand.length()==0 || toPrint==null || toPrint.length()==0) System.out.println(0);
        char[] colors = inHand.toCharArray();
        char[] boards = toPrint.toCharArray();
        HashMap<Character, Integer> map = new HashMap<>();
        for (int i = 0; i < colors.length; i++) { 
            if(Character.isUpperCase(colors[i])){ 
                map.put(colors[i],map.getOrDefault(colors[i],0)+1);
            }
        }
        int count = 0;
        for (int i = 0; i < boards.length; i++) { 
            if(Character.isUpperCase(boards[i])){ 
                if(map.containsKey(boards[i]) && map.get(boards[i])>=1){ 
                    map.put(boards[i],map.get(boards[i])-1);
                    count++;
                }
            }
        }
        System.out.println(count);
    }
}

第二题 迷宫dfs

// 输入描述
// 多组数据，第1行有1个正整数T，表示有T组数据。（T<=100）
//
// 对于每组数据，第1行有两个整数N和M。(1<=N, M<=1000)
//
// 接着N行，每行有一个长度为M的字符串，表示N*M的迷宫。
//
// 输出描述
// 输出一个整数，表示使用特异功能的最少次数。如果小昆虫不能走出迷宫，则输出-1。
import java.util.Arrays;
import java.util.Scanner;

    public class Main { 
        static boolean flag;
        static int ans;
        static int[][] dir = new int[][] {  {  -1, 0 }, {  1, 0 }, {  0, -1 }, {  0, 1 } };
        static boolean[][] vis;
        static int[][] cost;

        public static void main(String[] args) { 
            Scanner in = new Scanner(System.in);
            int T = in.nextInt();
            int n, m, sx, sy;
            char[][] map;

            while (T-- > 0) { 
                n = in.nextInt();
                m = in.nextInt();
                in.nextLine();
                map = new char[n][m];
                vis = new boolean[n][m];
                cost = new int[n][m];
                for (int i = 0; i < n; i++) { 
                    map[i] = in.next().toCharArray();
                    Arrays.fill(cost[i], 0x3f3f3f3f);
                }
                sx = 0;
                sy = 0;
                for (int i = 0; i < n; i++) { 
                    for (int j = 0; j < m; j++) { 
                        if (map[i][j] == '@') { 
                            sx = i;
                            sy = j;
                        }
                    }
                }
                flag = false;
                vis[sx][sy] = true;
                dfs(sx, sy, map, n, m);
                if (flag) { 
                    System.out.println(0);
                    continue;
                }
                flag = false;
                ans = Integer.MAX_VALUE;
                cost[sx][sy] = 0;
                dfs(sx, sy, map, n, m, cost[sx][sy]);
                System.out.println(flag ? ans : -1);
            }
        }

        static void dfs(int x, int y, char[][] map, int n, int m) { 
            if (flag)
                return;
            for (int i = 0; i < 4; i++) { 
                int dx = x + dir[i][0], dy = y + dir[i][1];
                // 出界了
                if (!check(dx, dy, n, m)) { 
                    flag = true;
                } else if (!vis[dx][dy] && map[dx][dy] == '.') { 
                    vis[dx][dy] = true;
                    dfs(dx, dy, map, n, m);
                }
            }
        }

        static void dfs(int x, int y, char[][] map, int n, int m, int cnt) { 
            for (int i = 0; i < 4; i++) { 
                int dx = x + dir[i][0], dy = y + dir[i][1];
                // 出界了
                if (!check(dx, dy, n, m)) { 
                    flag = true;
                    ans = Math.min(ans, cnt);
                } else if (map[dx][dy] != '#') { 
                    if (map[dx][dy] == '*' && cost[x][y] + 1 < cost[dx][dy]) { 
                        cost[dx][dy] = cost[x][y] + 1;
                        dfs(dx, dy, map, n, m, cost[dx][dy]);
                    } else if (map[dx][dy] == '.' && cost[x][y] < cost[dx][dy]) { 
                        cost[dx][dy] = cost[x][y];
                        dfs(dx, dy, map, n, m, cost[dx][dy]);
                    }
                }
            }
        }

        static boolean check(int x, int y, int n, int m) { 
            return x >= 0 && y >= 0 && x < n && y < m;
        }
    }