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代码的鲁棒性:树的子结构

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)

代码实现方式一:

/**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) || HasSubtree(root1.left, root2)                || HasSubtree(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;    }}

 

代码实现方式二:

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

 

代码的鲁棒性:树的子结构