题目：

题解：

int sumNumbers(struct TreeNode* root) {
    if (root == NULL) {
        return 0;
    }
    int sum = 0;
    struct TreeNode* nodeQueue[2000];
    int numQueue[2000];
    int leftQueue = 0, rightQueue = 0;
    nodeQueue[rightQueue] = root;
    numQueue[rightQueue++] = root->val;
    while (leftQueue < rightQueue) {
        struct TreeNode* node = nodeQueue[leftQueue];
        int num = numQueue[leftQueue++];
        struct TreeNode* left = node->left;
        struct TreeNode* right = node->right;
        if (left == NULL && right == NULL) {
            sum += num;
        } else {
            if (left != NULL) {
                nodeQueue[rightQueue] = left;
                numQueue[rightQueue++] = num * 10 + left->val;
            }
            if (right != NULL) {
                nodeQueue[rightQueue] = right;
                numQueue[rightQueue++] = num * 10 + right->val;
            }
        }
    }
    return sum;
}