左叶子之和
cpp
class Solution {
public:
int sumOfLeftLeaves(TreeNode* root) {
if(root==NULL) return 0;
if(root->left==NULL&&root->right==NULL) return 0;
int ln=sumOfLeftLeaves(root->left);
if(root->left!=NULL&&root->left->left==NULL&&root->left->right==NULL) ln=root->left->val;
int rn=sumOfLeftLeaves(root->right);
int sum=ln+rn;
return sum;
}
};
