剑指offer 二叉树中和为某一值的路径

ArrayList<ArrayList<Integer>> results = new ArrayList<>();

public ArrayList<ArrayList<Integer>> FindPath(TreeNode root,int target) {
if (root == null) {
return new ArrayList<>();
}
int curSum = 0;
int[] path = new int[1002];
int index= 0;
FindPath(root,target,path,index,curSum);
return results;
}

public void FindPath(TreeNode root,int target,int[] path,int index,int curSum){
if (root == null) {
return;
}
curSum += root.val;
path[index++] = root.val;
boolean isLeaf = root.left == null && root.right == null;
if (curSum == target && isLeaf) {
ArrayList<Integer> plist = new ArrayList<>();
for (int i = 0; i < index; ++i) {
plist.add(path[i]);
}
results.add(plist);
return;
}
if (curSum < target && root.left != null) {
FindPath(root.left,target,path,index,curSum);
}
if (curSum < target && root.right != null) {
FindPath(root.right,target,path,index,curSum);
}
}