qiuqiusama721
commented
2 months ago // java版本 // 标记方式为将1变为2，最后在输出前再将2变为1 import java.util.Scanner;
public class Main { public static final int[][] dir = {{0, 1}, {0, -1}, {1, 0}, {-1, 0}}; public static void main(String[] args) { Scanner sc = new Scanner(System.in); int n = sc.nextInt(); int m = sc.nextInt(); int[][] grid = new int[n][m]; for (int i = 0; i < n; i++) { for (int j = 0; j < m; j++) { grid[i][j] = sc.nextInt(); } } for (int i = 0; i < n; i++) { if (grid[i][0] == 1) { grid[i][0] = 2; dfs(grid, i, 0, 2); } if (grid[i][m - 1] == 1) { grid[i][m - 1] = 2; dfs(grid, i, m - 1, 2); } } for (int j = 1; j < m - 1; j++) { if (grid[0][j] == 1) { grid[0][j] = 2; dfs(grid, 0, j, 2); } if (grid[n - 1][j] == 1) { grid[n - 1][j] = 2; dfs(grid, n - 1, j, 2); } } for (int i = 1; i < n - 1; i++) { for (int j = 1; j < m - 1; j++) { if (grid[i][j] == 1) { grid[i][j] = 0; dfs(grid, i, j, 0); } } } for (int i = 0; i < n; i++) { for (int j = 0; j < m; j++) { if (grid[i][j] == 2) { grid[i][j] = 1; } } } for (int i = 0; i < n; i++) { for (int j = 0; j < m - 1; j++) { System.out.print(grid[i][j] + " "); } System.out.println(grid[i][m - 1]); } } public static void dfs(int[][] grid, int x, int y, int key) { for (int i = 0; i < 4; i++) { int nextX = x + dir[i][0]; int nextY = y + dir[i][1]; if (nextX >= 0 && nextY >= 0 && nextX < grid.length && nextY < grid[0].length && grid[nextX][nextY] == 1) { grid[nextX][nextY] = key; dfs(grid, nextX, nextY, key); } } } }
https://www.programmercarl.com/kamacoder/0102.%E6%B2%89%E6%B2%A1%E5%AD%A4%E5%B2%9B.html