輸入兩棵二叉樹A,B,判斷B是不是A的子結構。(ps:我們約定空樹不是任意一個樹的子結構)
/**
public class TreeNode {
int val = 0;
TreeNode left = null;
TreeNode right = null;
public TreeNode(int val) {
this.val = val;
}
}
*/
public class Solution {
public boolean HasSubtree(TreeNode root1,TreeNode root2) {
if(root1==null||root2==null){
return false;
}
return isSubtree(root1,root2)||isSubtree(root1.left,root2)||isSubtree(root1.right,root2);
}
public boolean isSubtree(TreeNode root1,TreeNode root2){
if(root2==null){
return true;
}
if(root1==null){
return false;
}
if(root1.val==root2.val){
return isSubtree(root1.left,root2.left)&&isSubtree(root1.right,root2.right);
}else{
return false;
}
}
}