BiruLyu
7/5/2017 - 8:49 PM

## 404. Sum of Left Leaves(1st).java

``````/**
* Definition for a binary tree node.
* public class TreeNode {
*     int val;
*     TreeNode left;
*     TreeNode right;
*     TreeNode(int x) { val = x; }
* }
*/
public class Solution {
private void addLeftLeaves(TreeNode root, int[] res, boolean flag) {
if (root == null) return;
if (flag && root.left == null && root.right == null) res[0] += root.val;
if (root.left != null) addLeftLeaves(root.left, res, true);
if (root.right != null) addLeftLeaves(root.right, res, false);
}
public int sumOfLeftLeaves(TreeNode root) {
int[] res = new int[] {0};
return res[0];
}
}``````
``````/**
* Definition for a binary tree node.
* public class TreeNode {
*     int val;
*     TreeNode left;
*     TreeNode right;
*     TreeNode(int x) { val = x; }
* }
*/
public class Solution {
public int sumOfLeftLeaves(TreeNode root) {
if(root == null) return 0;

int ans = 0;
if(root.left != null){
if(root.left.left == null && root.left.right == null)
ans += root.left.val;
else
ans += sumOfLeftLeaves(root.left);
}
ans += sumOfLeftLeaves(root.right);
return ans;
}
}``````