华为OD机试-战场索敌-DFS（JAVA 2025A卷）

import java.util.*;
public class FindArmy {
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        int[] ints = Arrays.stream(sc.nextLine().split("\\s+")).mapToInt(Integer::parseInt).toArray();
        int row = ints[0],column = ints[1],k=ints[2];
        char[][] chars = new char[row][column];
        for (int i = 0; i < row; i++) {
            chars[i] = sc.nextLine().toCharArray();
        }
        solve(chars,k);
    }

    private static void solve(char[][] chars, int k) {
        int sum = 0;
        for (int i = 0; i < chars.length; i++) {
            for (int j = 0; j < chars[0].length; j++) {
                if(chars[i][j]!='#'&&dfs(chars,i,j)<k){
                    sum++;
                }
            }
        }
        System.out.println(sum);
    }

    private static int dfs(char[][] chars,int i, int j) {
        int cnt = 0;
        if(i<0||i>=chars.length||j<0||j>=chars[0].length||chars[i][j]=='#'){
            return cnt;
        }
        if(chars[i][j]=='E'){
            cnt++;
        }
        chars[i][j]='#';
        cnt+=dfs(chars,i+1,j);
        cnt+=dfs(chars,i-1,j);
        cnt+=dfs(chars,i,j+1);
        cnt+=dfs(chars,i,j-1);
        return cnt;
    }
}