-
Notifications
You must be signed in to change notification settings - Fork 2
Expand file tree
/
Copy pathLeetCode130.java
More file actions
105 lines (99 loc) · 2.76 KB
/
LeetCode130.java
File metadata and controls
105 lines (99 loc) · 2.76 KB
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
package problems;
import java.util.LinkedList;
import java.util.Queue;
/**
* DFS
*/
public class LeetCode130 {
int n, m;
public void solve(char[][] board) {
n = board.length;
if (n == 0) {
return;
}
m = board[0].length;
for (int i = 0; i < n; i++) {
dfs(board, i, 0);
dfs(board, i, m - 1);
}
for (int i = 1; i < m - 1; i++) {
dfs(board, 0, i);
dfs(board, n - 1, i);
}
for (int i = 0; i < n; i++) {
for (int j = 0; j < m; j++) {
if (board[i][j] == 'A') {
board[i][j] = 'O';
} else if (board[i][j] == 'O') {
board[i][j] = 'X';
}
}
}
}
public void dfs(char[][] board, int x, int y) {
if (x < 0 || x >= n || y < 0 || y >= m || board[x][y] != 'O') {
return;
}
board[x][y] = 'A';
dfs(board, x + 1, y);
dfs(board, x - 1, y);
dfs(board, x, y + 1);
dfs(board, x, y - 1);
}
}
/**
* BFS
*/
class LeetCode130_1 {
int[] dx = {1, -1, 0, 0};
int[] dy = {0, 0, 1, -1};
public void solve(char[][] board) {
int n = board.length;
if(n == 0) {
return;
}
int m = board[0].length;
Queue<int[]> queue = new LinkedList<int[]>();
for (int i = 0; i < n; i++) {
if (board[i][0] == 'O') {
queue.offer(new int[]{i, 0});
board[i][0] = 'A';
}
if (board[i][m - 1] == 'O') {
queue.offer(new int[]{i, m - 1});
board[i][m - 1] = 'A';
}
}
for (int i = 1; i < m - 1; i++) {
if (board[0][i] == 'O') {
queue.offer(new int[]{0, i});
board[0][i] = 'A';
}
if (board[n - 1][i] == 'O') {
queue.offer(new int[]{n - 1, i});
board[n - 1][i] = 'A';
}
}
while (!queue.isEmpty()) {
int[] cell = queue.poll();
int x = cell[0], y = cell[1];
for (int i = 0; i < 4; i++) {
int mx = x + dx[i], my = y + dy[i];
if (mx < 0 || my < 0 || mx >= n || my >= m || board[mx][my] != 'O') {
continue;
}
queue.offer(new int[]{mx, my});
board[mx][my] = 'A';
}
}
for (int i = 0; i < n; i++) {
for (int j = 0; j < m; j++) {
if (board[i][j] == 'A') {
board[i][j] = 'O';
} else if (board[i][j] == 'O') {
board[i][j] = 'X';
}
}
}
}
}