剑指offer--序列化二叉树

题目描述

/*
public class TreeNode {
int val = 0;
TreeNode left = null;
TreeNode right = null;

public TreeNode(int val) {
this.val = val;

}

}
*/
import java.util.ArrayList;
public class Solution {
String Serialize(TreeNode root) {
if(root==null) return "";
StringBuilder sb = new StringBuilder();
ArrayList<TreeNode> queue = new ArrayList<TreeNode>();
ArrayList<String> result = new ArrayList<String>();
queue.add(root);
result.add(root.val+"");
int low = 0;
int high = 1;
while(low<high){
TreeNode t = queue.get(low);
if(t.left!=null){
result.add(t.left.val+"");
queue.add(t.left);
high++;
}else{
result.add("#");
}
if(t.right!=null){
result.add(t.right.val+"");
queue.add(t.right);
high++;
}else{
result.add("#");
}
low++;
}

int i;
for(i=result.size()-1;i<result.size();i--){
if(!result.get(i).endsWith("#")) break;
}
for(int j=0;j<=i;j++){
sb.append(result.get(j)).append(",");
}
return sb.deleteCharAt(sb.length()-1).toString();
}

TreeNode Deserialize(String str) {
if(str.length()==0) return null;
String[] chars = str.split(",");
ArrayList<TreeNode> queue = new ArrayList<TreeNode>();
TreeNode t = new TreeNode(Integer.valueOf(chars[0]));
queue.add(t);
int low = 0;
for(int i=0;i<chars.length && low<queue.size();){
t = queue.get(low);
if(i+1<chars.length){
i++;
TreeNode left = null;
if(!("#".equals(chars[i]))){
left = new TreeNode(Integer.valueOf(chars[i]));
queue.add(left);
}
t.left = left;
}
if(i+1<chars.length){
i++;
TreeNode right = null;
if(!"#".equals(chars[i])){
right = new TreeNode(Integer.valueOf(chars[i]));
queue.add(right);
}
t.right = right;
}
low++;
}
return queue.get(0);
}
}