题解 | #树的子结构#Java递归

/**
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 isTheSame(root1,root2) || HasSubtree(root1.left, root2) || HasSubtree(root1.right, root2);
    }
    boolean isTheSame(TreeNode root1,TreeNode root2){
        if(root2 == null){
            return true;
        }
        if(root1 == null)
            return false;
        if(root1.val != root2.val){
            return false;
        } 
        return isTheSame(root1.left,root2.left) && isTheSame(root1.right,root2.right);
    }
}