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| class TreeNode {
int val;
TreeNode left;
TreeNode right;
TreeNode(int x) {
val = x;
}
}
class Solution {
private int sum = 0;
public int sumOfLeftLeaves(TreeNode root) {
dfs(root);
return sum;
}
private void dfs(TreeNode root) {
if (root == null) {
return;
}
if (haveLeftLeave(root)) {
sum += root.left.val;
}
dfs(root.left);
dfs(root.right);
}
private boolean haveLeftLeave(TreeNode node) {
if (node == null) {
return false;
}
return node.left != null && node.left.left == null && node.left.right == null;
}
}
|
