404. Sum of Left Leaves

/**
 * Definition for a binary tree node.
 * public class TreeNode {
 *     int val;
 *     TreeNode left;
 *     TreeNode right;
 *     TreeNode(int x) { val = x; }
 * }
 */
public class Solution {
    int sum = 0;
    public int sumOfLeftLeaves(TreeNode root) {
        if(root == null) return 0;
        return getleft(root, false);
    }
    public int getleft(TreeNode root, boolean isLeft){
        if(root == null) return 0;
        if(root.left == null && root.right == null && isLeft) return root.val;
        return  getleft(root.left ,true) + getleft(root.right, false);
    }
}