Binary linked list to integer

Binary linked list to integer

Problem solution (C++)

class Solution {
    
    
public:
    int getDecimalValue(ListNode* head) {
    
    
        ListNode* cur = head;
        int ans = 0;
        while (cur != nullptr) {
    
    
            ans = ans * 2 + cur->val;
            cur = cur->next;
        }
        return ans;
    }
};

Icon

Detailed

1. Get the head node:
   (You don't need to quote cur here, call head directly, and quote cur to make the code logic clearer)
2. Traversal:
   (the first traversal to obtain the value of the first node, and then, perform operations)
   [traversal end condition: the value of the cur node is empty]
3. return value

difficulty

1. Master the calculation method of binary positive and negative sequence
   1>. Positive sequence:
   Example 1: 101
   ans = [(1*2)+0] 2+1
   Example 2: 10011
   ans = {[[(1 2)+0] 2+ 0] 2+1} 2 + 1
   2>. Reverse order:
   Example 1: 101
   ans = 1 (2^0) + 0 (2^1) + 1 (2^2)
   【Order from back to front】
2. And this question is the method of applying the positive sequence to calculate the binary

statement

1. Author: ELE
2. <Do not reprint without permission, welcome everyone to comment>