66 */
77public class CheckSubtree {
88
9- /*private static boolean isT2SubtreeofT1(TreeNode t1, TreeNode t2) {
10-
9+ private static boolean isT2SubtreeOfT1 (TreeNode t1 , TreeNode t2 ) {
10+ if (t1 == null ) {
11+ return false ;
12+ } else if (t2 == null ) {
13+ return true ;
14+ }
15+ 16+ if (t1 .val == t2 .val ) {
17+ if (matchTree (t1 , t2 )) {
18+ return true ;
19+ }
20+ }
21+ return isT2SubtreeOfT1 (t1 .left , t2 ) || isT2SubtreeOfT1 (t1 .right , t2 );
1122 }
12-
23+ 1324 private static boolean matchTree (TreeNode a , TreeNode b ) {
14- }*/
15- 25+ if (a == null && b == null ) {
26+ return true ;
27+ } else if (a == null ) {
28+ return false ;
29+ } else if (b == null ) {
30+ return true ;
31+ } else if (a .val != b .val ) {
32+ return false ;
33+ } else {
34+ return matchTree (a .left , b .left ) && matchTree (a .right , b .right );
35+ }
36+ }
37+ 1638 public static void main (String [] args ) {
39+ /*
40+ The BST looks like:
41+
42+ 4
43+ / \
44+ 2 8
45+ / \ / \
46+ 1 3 6 9
47+ /
48+ 0
49+
50+ */
51+ TreeNode treeRoot = new TreeNode (4 );
52+ treeRoot .left = new TreeNode (2 );
53+ treeRoot .right = new TreeNode (8 );
54+ treeRoot .left .left = new TreeNode (1 );
55+ treeRoot .left .right = new TreeNode (3 );
56+ treeRoot .left .left .left = new TreeNode (0 );
57+ treeRoot .right .left = new TreeNode (6 );
58+ treeRoot .right .right = new TreeNode (9 );
59+ System .out .println (isT2SubtreeOfT1 (treeRoot , treeRoot ));
60+ System .out .println (isT2SubtreeOfT1 (treeRoot , treeRoot .left ));
61+ System .out .println (isT2SubtreeOfT1 (treeRoot , treeRoot .right ));
62+ 63+ /*
64+ The sub-tree:
65+
66+ 8
67+ /
68+ 6
69+ */
70+ TreeNode treeRoot2 = new TreeNode (8 );
71+ treeRoot2 .left = new TreeNode (6 );
72+ System .out .println (isT2SubtreeOfT1 (treeRoot , treeRoot2 ));
73+ 74+ /*
75+ The sub-tree:
76+
77+ 8
78+ /
79+ 9
80+ */
81+ TreeNode treeRoot3 = new TreeNode (8 );
82+ treeRoot3 .left = new TreeNode (9 );
83+ System .out .println (isT2SubtreeOfT1 (treeRoot , treeRoot3 ));
1784 }
18- }
85+ }
0 commit comments