Leetcode——404. 左葉子之和

c++

/**
 * Definition for a binary tree node.
 * struct TreeNode {
 *     int val;
 *     TreeNode *left;
 *     TreeNode *right;
 *     TreeNode(int x) : val(x), left(NULL), right(NULL) {}
 * };
 */
class Solution 
{
public:
    int getSum(TreeNode* root,bool flag)
    {
        if(root==NULL)
            return 0;
        if(flag&&root->left==NULL&&root->right==NULL)
            return root->val;
        else
            return getSum(root->left,true)+getSum(root->right,false);
    }
    int sumOfLeftLeaves(TreeNode* root) 
    {
        return getSum(root,false);
    }
};

python

# Definition for a binary tree node.
# class TreeNode:
#     def __init__(self, x):
#         self.val = x
#         self.left = None
#         self.right = None

class Solution:
    def getSum(self,root,flag):
        if root==None:
            return 0
        if flag and root.left==None and root.right==None:
            return root.val
        else:
            return self.getSum(root.left,True)+self.getSum(root.right,False)
    def sumOfLeftLeaves(self, root: TreeNode) -> int:
        return self.getSum(root,False)

注意python關鍵字
c++的NULL對於None
true爲True
false爲False
類裏面的函數調用需要加self關鍵字（c++裏面類裏面調用類中定義的函數不需要，直接調用就好）