树的子结构

Desicription

输入两棵二叉树A,B,判断B是不是A的子结构。(ps:我们约定空树不是任意一个树的子结构)

Solution

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
/*
struct TreeNode {
int val;
struct TreeNode *left;
struct TreeNode *right;
TreeNode(int x) :
val(x), left(NULL), right(NULL) {
}
};*/
class Solution {
private:
bool IsSubtree(TreeNode* pRoot1, TreeNode* pRoot2) {
if(pRoot2 == nullptr) {
return true;
} else if(pRoot1 == nullptr) {
return false;
} else if(pRoot1->val != pRoot2->val) {
return false;
}
return IsSubtree(pRoot1->left, pRoot2->left) && IsSubtree(pRoot1->right, pRoot2->right);
}
public:
bool HasSubtree(TreeNode* pRoot1, TreeNode* pRoot2) {
if(pRoot1 == nullptr || pRoot2 == nullptr) {
return false;
}
bool result = false;
if(pRoot1->val == pRoot2->val) {
result = IsSubtree(pRoot1, pRoot2);
}
if(!result) {
result = IsSubtree(pRoot1->left, pRoot2);
}
if(!result) {
result = IsSubtree(pRoot1->right, pRoot2);
}
return result;
}
};