why putting loop above left and right function call is successfully submitting and when putting it below left and right function call is giving TLE - data-structures

Question

I am working on the GeeksForGeeks code challenge K Sum Paths:
Given a binary tree and an integer K. Find the number of paths in the tree which have their sum equal to K.A path may start from any node and end at any node in the downward direction.
Input:
Tree =
1
/ \
3 -1
/ \ / \
2 1 4 5
/ / \ \
1 1 2 6
K = 5
Output: 8
Explanation:
The following paths sum to K.
3 2
3 1 1
1 3 1
4 1
1 -1 4 1
-1 4 2
5
1 -1 5
My first solution was this which was giving time limit exceeded.
class Solution {
int count = 0;
public int sumK(Node root,int k)
{
ArrayList<Integer> list = new ArrayList<>();
sum(root,k,list);
int ans = count;
return ans;
}
void sum(Node root, int k,ArrayList<Integer> list){
if( root == null) return;
list.add(root.data);
sum(root.left,k,list);
sum(root.right, k,list);
int sum = 0;
for(int i = list.size()-1;i>=0;i--){
sum+=list.get(i);
if(sum==k) count++;
}
list.remove(list.size()-1);
}
}
After putting the loop above the function calls it was successfully submitted. Why is that? Can anyone explain?.
class Solution {
int count = 0;
public int sumK(Node root,int k)
{
ArrayList<Integer> list = new ArrayList<>();
sum(root,k,list);
int ans = count;
return ans;
}
void sum(Node root, int k,ArrayList<Integer> list){
if( root == null) return;
list.add(root.data);
int sum = 0;
for(int i = list.size()-1;i>=0;i--){
sum+=list.get(i);
if(sum==k) count++;
}
sum(root.left,k,list);
sum(root.right, k,list);
list.remove(list.size()-1);
}
}