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| class Solution {
static final int dirs[][] = new int[][]{{-1, 0}, {1, 0}, {0, -1}, {0, 1}};
public int orangesRotting(int[][] grid) {
int m = grid.length, n = grid[0].length, ans = 0, cnt = 0;
Deque<int[]> queue = new ArrayDeque<>();
for (int i = 0; i < m; ++i) {
for (int j = 0; j < n; ++j) {
if (grid[i][j] == 1) {
++cnt;
} else if (grid[i][j] == 2) {
queue.offer(new int[]{i, j});
}
}
}
while (!queue.isEmpty() && cnt > 0) {
for (int size = queue.size(); size > 0; --size) {
int[] cur = queue.poll();
int x = cur[0], y = cur[1];
for (int[] dir : dirs) {
int nx = x + dir[0], ny = y + dir[1];
if (nx >= 0 && nx < m && ny >= 0 && ny < n && grid[nx][ny] == 1) {
--cnt;
grid[nx][ny] = 2;
queue.offer(new int[]{nx, ny});
}
}
}
++ans;
}
return cnt > 0 ? -1 : ans;
}
}
|
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