1022. Sum of Root To Leaf Binary Numbers从根到叶的二进制数之和

网址：https://leetcode.com/problems/sum-of-root-to-leaf-binary-numbers/

递归调用求和，同时注意%1000000007的位置

/**
 * 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 getNum(TreeNode* t, int sum)
    {
        if(sum >= 1000000007)
            sum %= 1000000007;
        if(t->left == NULL && t->right == NULL)
        {
            return sum*2+t->val;
        }
            
        if(t->right && t->left)
            return getNum(t->left, sum*2+t->val)%1000000007+getNum(t->right, sum*2+t->val)%1000000007;
        else
            if(t->left)
                return getNum(t->left, sum*2+t->val);
            else
                return getNum(t->right, sum*2+t->val);
    }   
    int sumRootToLeaf(TreeNode* root)
    {
        int ans = 0;
        ans = getNum(root, ans);
        return ans%1000000007;
    }
};