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| class Solution {
private static final int[][] DIRECTIONS = new int[][]{{1, 0}, {-1, 0}, {0, 1}, {0, -1}};
private static class State {
private boolean closed = true;
}
public int closedIsland(int[][] grid) {
int m = grid.length, n = grid[0].length;
int closedIslands = 0;
for (int i = 0; i < m; i++) {
for (int j = 0; j < n; j++) {
if (grid[i][j] == 0) {
State state = new State();
dfs(state, grid, i, j);
if (state.closed) {
closedIslands++;
}
}
}
}
return closedIslands;
}
private void dfs(State state, int[][] grid, int i, int j) {
int m = grid.length, n = grid[0].length;
grid[i][j] = 2;
for (int[] direction : DIRECTIONS) {
int nextI = i + direction[0], nextJ = j + direction[1];
if (nextI >= 0 && nextI < m && nextJ >= 0 && nextJ < n) {
if (grid[nextI][nextJ] == 0) {
dfs(state, grid, nextI, nextJ);
}
} else {
state.closed = false;
}
}
}
}
|