117 lines
3.4 KiB
Java
117 lines
3.4 KiB
Java
//有一个二维矩阵 grid ，每个位置要么是陆地（记号为 0 ）要么是水域（记号为 1 ）。
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//
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// 我们从一块陆地出发，每次可以往上下左右 4 个方向相邻区域走，能走到的所有陆地区域，我们将其称为一座「岛屿」。
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//
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// 如果一座岛屿 完全 由水域包围，即陆地边缘上下左右所有相邻区域都是水域，那么我们将其称为 「封闭岛屿」。
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//
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// 请返回封闭岛屿的数目。
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//
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//
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//
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// 示例 1：
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//
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//
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//
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// 输入：grid = [[1,1,1,1,1,1,1,0],[1,0,0,0,0,1,1,0],[1,0,1,0,1,1,1,0],[1,0,0,0,0,1
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//,0,1],[1,1,1,1,1,1,1,0]]
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//输出：2
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//解释：
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//灰色区域的岛屿是封闭岛屿，因为这座岛屿完全被水域包围（即被 1 区域包围）。
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//
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// 示例 2：
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//
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//
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//
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// 输入：grid = [[0,0,1,0,0],[0,1,0,1,0],[0,1,1,1,0]]
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//输出：1
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//
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//
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// 示例 3：
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//
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// 输入：grid = [[1,1,1,1,1,1,1],
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// [1,0,0,0,0,0,1],
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// [1,0,1,1,1,0,1],
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// [1,0,1,0,1,0,1],
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// [1,0,1,1,1,0,1],
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// [1,0,0,0,0,0,1],
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// [1,1,1,1,1,1,1]]
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//输出：2
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//
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//
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//
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//
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// 提示：
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//
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//
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// 1 <= grid.length, grid[0].length <= 100
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// 0 <= grid[i][j] <=1
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//
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// Related Topics 深度优先搜索 广度优先搜索 并查集 数组 矩阵
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// 👍 83 👎 0
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package leetcode.editor.cn;
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import com.code.leet.entiy.TwoArray;
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//1254:统计封闭岛屿的数目
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public class NumberOfClosedIslands {
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public static void main(String[] args) {
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//测试代码
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Solution solution = new NumberOfClosedIslands().new Solution();
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TwoArray twoArray = new TwoArray("" +
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"[[1,1,1,1,1,1,1,0]," +
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"[1,0,0,0,0,1,1,0]," +
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"[1,0,1,0,1,1,1,0]," +
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"[1,0,0,0,0,1,0,1]," +
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"[1,1,1,1,1,1,1,0]]", true
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);
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System.out.println(solution.closedIsland(twoArray.getArr()));
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}
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//力扣代码
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//leetcode submit region begin(Prohibit modification and deletion)
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class Solution {
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boolean[][] use;
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int[] dx = new int[]{-1, 1, 0, 0};
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int[] dy = new int[]{0, 0, -1, 1};
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int count = 0;
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boolean flag;
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public int closedIsland(int[][] grid) {
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use = new boolean[grid.length][grid[0].length];
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for (int i = 0; i < grid.length; i++) {
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for (int j = 0; j < grid[0].length; j++) {
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if (grid[i][j] == 0 && !use[i][j]) {
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flag = true;
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dfs(i, j, grid);
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if (flag) {
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count++;
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}
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}
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}
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}
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return count;
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}
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private void dfs(int x, int y, int[][] grid) {
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use[x][y] = true;
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for (int i = 0; i < 4; i++) {
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x += dx[i];
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y += dy[i];
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if (x < 0 || x >= grid.length || y < 0 || y >= grid[0].length) {
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x -= dx[i];
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y -= dy[i];
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flag = false;
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continue;
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}
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if (grid[x][y] == 0 && !use[x][y]) {
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dfs(x, y, grid);
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}
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x -= dx[i];
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y -= dy[i];
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}
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}
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}
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//leetcode submit region end(Prohibit modification and deletion)
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} |