private static String sequenceTree(TreeNode<Integer> head) {
if(head==null)
return "#!";
String res = String.valueOf(head.item)+"!";
res += sequenceTree(head.left);
res += sequenceTree(head.right);
return res;
}
// 使用前序遍历来反序列化
// seq="10!3!2!#!#!4!#!7!5!#!#!9!8!#!#!#!11!#!12!#!20!#!23!#!#!"
private static TreeNode<Integer> reconByString(String seq) {
String[] value = seq.split("!");
Queue<String> queue = new LinkedList<String>();
for(int i=0;i!=value.length;i++)
queue.offer(value[i]);
return reconPreOrder(queue);
}
private static TreeNode<Integer> reconPreOrder(Queue<String> queue) {
String value =queue.poll();
if(value.equals("#"))
return null;
TreeNode head = new TreeNode(Integer.valueOf(value));
head.left = reconPreOrder(queue);
head.right = reconPreOrder(queue);
return head;
}
// 使用层次遍历来反序列化
private static String sequenceTreeByLevel(TreeNode head){
if(head==null)
return "#!";
String res = head.value+"!";
Queue<Node> queue = new LinkedList<Node>();
queue.offer(head);
while(!queue.isEmpty()){
head = queue.poll();
if(head.left!=null){
res+=head.left.value+"!";
queue.offer(head.left);
}else{
res+="#!";
}
if(head.right!=null){
res+=head.right.value+"!";
queue.offer(head.right);
}else{
res+="#!";
}
}
return res;
}
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