import java.util.ArrayList;
/**
public class TreeNode {
int val = 0;
TreeNode left = null;
TreeNode right = null;
public TreeNode(int val) {
this.val = val;
}
}
*/
/*
//按照长度从大到小排出的算法代码,匿名内部类的方式
Collections.Sort(listAll, new Comparator<ArrayList<Integer>>(){
@Override
public int Compare(ArrayList<Integer> o1, ArrayList<Integer> o2){
if(o1 < o2){
return 1;
}else{
return -1;
}
}
});
*/
public class Solution {
//调用自身的递归,必须把这种声明放在方法体外面,否则每次递归都重新定义一遍
ArrayList<ArrayList<Integer>> listAll = new ArrayList<>();
ArrayList<Integer> list = new ArrayList<>();
public ArrayList<ArrayList<Integer>> FindPath(TreeNode root,int target) {
if(root == null)return listAll;
list.add(root.val);
target -= root.val;
if(target == 0 && root.left == null && root.right == null){
listAll.add(new ArrayList<>(list));
}
FindPath(root.left, target);
FindPath(root.right, target);
list.remove(list.size() - 1);//遍历到叶子节点还未找到则回退到父节点,(深度搜索)
return listAll;
}
}