给定一个包含了一些 0 和 1 的非空二维数组 grid 。
一个 岛屿 是由一些相邻的 1 (代表土地) 构成的组合,这里的「相邻」要求两个 1 必须在水平或者竖直方向上相邻。你可以假设 grid 的四个边缘都被 0(代表水)包围着。
找到给定的二维数组中最大的岛屿面积。(如果没有岛屿,则返回面积为 0 。)
示例 1:
[[0,0,1,0,0,0,0,1,0,0,0,0,0],
[0,0,0,0,0,0,0,1,1,1,0,0,0],
[0,1,1,0,1,0,0,0,0,0,0,0,0],
[0,1,0,0,1,1,0,0,1,0,1,0,0],
[0,1,0,0,1,1,0,0,1,1,1,0,0],
[0,0,0,0,0,0,0,0,0,0,1,0,0],
[0,0,0,0,0,0,0,1,1,1,0,0,0],
[0,0,0,0,0,0,0,1,1,0,0,0,0]]
对于上面这个给定矩阵应返回 6。注意答案不应该是 11 ,因为岛屿只能包含水平或垂直的四个方向的 1 。
示例 2:
[[0,0,0,0,0,0,0,0]]
对于上面这个给定的矩阵, 返回 0。
java代码:
class Solution {
public int maxAreaOfIsland(int[][] grid) {
int ans = 0;
for (int i = 0; i != grid.length; ++i) {
for (int j = 0; j != grid[0].length; ++j) {
int cur = 0;
Deque<Integer> stacki = new LinkedList<Integer>();
Deque<Integer> stackj = new LinkedList<Integer>();
stacki.push(i);
stackj.push(j);
while (!stacki.isEmpty()) {
int cur_i = stacki.pop(), cur_j = stackj.pop();
if (cur_i < 0 || cur_j < 0 || cur_i == grid.length || cur_j == grid[0].length || grid[cur_i][cur_j] != 1) {
continue;
}
++cur;
grid[cur_i][cur_j] = 0;
int[] di = {0, 0, 1, -1};
int[] dj = {1, -1, 0, 0};
for (int index = 0; index != 4; ++index) {
int next_i = cur_i + di[index], next_j = cur_j + dj[index];
stacki.push(next_i);
stackj.push(next_j);
}
}
ans = Math.max(ans, cur);
}
}
return ans;
}
}