问题：
方法： 序列化与反序列化均通过递归实现，序列化时每一个子树用()包裹，层层包裹，最后输出1(2(3)(4))()形式的序列；反序列化时逻辑相反，通过()层层进入，从最底层开始还原节点，最后递归返回到上层，设置左子树和右子树，最后递归到根节点输出即为原树。
具体实现：
// Encodes a tree to a single string.
public String serialize(TreeNode root) {
if (root == null)
return "";
if (root.left == null && root.right == null)
return root.val + "";
else if (root.left == null)
return root.val + "()" + "(" + serialize(root.right) + ")";
else if (root.right == null)
return root.val + "(" + serialize(root.left) + ")";
return root.val + "(" + serialize(root.left) + ")" + "(" + serialize(root.right) + ")";
}
// Decodes your encoded data to tree.
public TreeNode deserialize(String s) {
if (s == null || s.length() == 0) return null;
int firstParen = s.indexOf("(");
int val = firstParen == -1 ? Integer.parseInt(s) : Integer.parseInt(s.substring(0, firstParen));
TreeNode cur = new TreeNode(val);
if (firstParen == -1) return cur;
int start = firstParen, leftParenCount = 0;
for (int i = start; i < s.length(); i++) {
if (s.charAt(i) == '(') leftParenCount++;
else if (s.charAt(i) == ')') leftParenCount--;
if (leftParenCount == 0 && start == firstParen) {
cur.left = deserialize(s.substring(start + 1, i));
start = i + 1;
} else if (leftParenCount == 0) {
cur.right = deserialize(s.substring(start + 1, i));
}
}
return cur;
}
public static void main(String args[]) {
}
有问题随时沟通
