[404] Sum of Left Leaves

暖身題也搞了好半天Orz tree真難ToT

/**

* Definition for a binary tree node.

* struct TreeNode {

* int val;

* struct TreeNode *left;

* struct TreeNode *right;

* };

*/

int dfs(struct TreeNode* root)

{

if (root==NULL)

return 0;

if (root->left != NULL && root->left->left == NULL && root->left->right == NULL)

return root->left->val + dfs(root->left) + dfs(root->right);

return dfs(root->left)+dfs(root->right);

}

int sumOfLeftLeaves(struct TreeNode* root) {

return dfs(root);

}