-
Notifications
You must be signed in to change notification settings - Fork 0
/
Leetcode00051.java
66 lines (60 loc) · 1.48 KB
/
Leetcode00051.java
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
import java.util.LinkedList;
import java.util.List;
/**
* 51. N-Queens
*
* @link https://leetcode.com/problems/n-queens
* @author vutiendat3601
* @date 2024-07-10
*/
public class Leetcode00051 {
private int[] queens;
private int n;
private List<List<String>> result;
public List<List<String>> solveNQueens(int n) {
this.n = n;
queens = new int[n];
result = new LinkedList<>();
put(0);
return result;
}
public void put(int row) {
if (row == n) {
final List<String> newResult = new LinkedList<>();
for (int pos : queens) {
String resultStr = "";
for (int i = 0; i < n; i++) {
if (i == pos) {
resultStr += "Q";
} else {
resultStr += ".";
}
}
newResult.add(resultStr);
}
result.add(newResult);
}
for (int col = 0; col < n; col++) {
int lastRow = row - 1;
boolean available = true;
while (lastRow >= 0) {
if (queens[lastRow] == col || Math.abs(col - queens[lastRow]) == row - lastRow) {
available = false;
break;
}
lastRow--;
}
if (available) {
queens[row] = col;
put(row + 1);
queens[row] = 0;
}
}
}
public static void main(String[] args) {
final int n = 4;
final Leetcode00051 leetcode00051 = new Leetcode00051();
final List<List<String>> result = leetcode00051.solveNQueens(n);
result.forEach(System.out::println);
}
}