/**
* Definition for singly-linked list.
* struct ListNode {
* int val;
* ListNode *next;
* ListNode(int x) : val(x), next(NULL) {}
* };
*/
class Solution {
public:
int getDecimalValue(ListNode* head) {
int ans = 0;
ListNode* now = head;
while(now!=NULL){
ans <<=1;
ans += now->val;
now = now->next;
}
return ans;
}
};