forked from varunu28/LeetCode-Java-Solutions
-
Notifications
You must be signed in to change notification settings - Fork 0
Expand file tree
/
Copy pathConstruct Quad Tree.java
More file actions
75 lines (69 loc) · 1.97 KB
/
Construct Quad Tree.java
File metadata and controls
75 lines (69 loc) · 1.97 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
/*
// Definition for a QuadTree node.
class Node {
public boolean val;
public boolean isLeaf;
public Node topLeft;
public Node topRight;
public Node bottomLeft;
public Node bottomRight;
public Node() {
this.val = false;
this.isLeaf = false;
this.topLeft = null;
this.topRight = null;
this.bottomLeft = null;
this.bottomRight = null;
}
public Node(boolean val, boolean isLeaf) {
this.val = val;
this.isLeaf = isLeaf;
this.topLeft = null;
this.topRight = null;
this.bottomLeft = null;
this.bottomRight = null;
}
public Node(boolean val, boolean isLeaf, Node topLeft, Node topRight, Node bottomLeft, Node bottomRight) {
this.val = val;
this.isLeaf = isLeaf;
this.topLeft = topLeft;
this.topRight = topRight;
this.bottomLeft = bottomLeft;
this.bottomRight = bottomRight;
}
};
*/
class Solution {
public Node construct(int[][] grid) {
return helper(grid, 0, 0, grid.length);
}
private Node helper(int[][] grid, int x, int y, int len) {
if (len == 1) {
return new Node(grid[x][y] != 0, true, null, null, null, null);
}
Node result = new Node();
Node topLeft = helper(grid, x, y, len / 2);
Node topRight = helper(grid, x, y + len / 2, len / 2);
Node bottomLeft = helper(grid, x + len / 2, y, len / 2);
Node bottomRight = helper(grid, x + len / 2, y + len / 2, len / 2);
if (
topLeft.isLeaf &&
topRight.isLeaf &&
bottomLeft.isLeaf &&
bottomRight.isLeaf &&
topLeft.val == topRight.val &&
topRight.val == bottomLeft.val &&
bottomLeft.val == bottomRight.val
) {
result.isLeaf = true;
result.val = topLeft.val;
}
else {
result.topLeft = topLeft;
result.topRight = topRight;
result.bottomLeft = bottomLeft;
result.bottomRight = bottomRight;
}
return result;
}
}