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81 lines
1.7 KiB
Markdown
81 lines
1.7 KiB
Markdown
# [1290. Convert Binary Number in a Linked List to Integer](https://leetcode.com/problems/convert-binary-number-in-a-linked-list-to-integer/)
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## 题目
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Given `head` which is a reference node to a singly-linked list. The value of each node in the linked list is either 0 or 1. The linked list holds the binary representation of a number.
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Return the *decimal value* of the number in the linked list.
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**Example 1**:
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```
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Input: head = [1,0,1]
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Output: 5
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Explanation: (101) in base 2 = (5) in base 10
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```
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**Example 2**:
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```
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Input: head = [0]
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Output: 0
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```
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**Example 3**:
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```
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Input: head = [1]
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Output: 1
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```
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**Example 4**:
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```
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Input: head = [1,0,0,1,0,0,1,1,1,0,0,0,0,0,0]
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Output: 18880
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```
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**Example 5**:
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```
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Input: head = [0,0]
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Output: 0
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```
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**Constraints**:
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- The Linked List is not empty.
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- Number of nodes will not exceed `30`.
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- Each node's value is either `0` or `1`.
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## 题目大意
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给你一个单链表的引用结点 head。链表中每个结点的值不是 0 就是 1。已知此链表是一个整数数字的二进制表示形式。请你返回该链表所表示数字的 十进制值 。
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提示：
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- 链表不为空。
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- 链表的结点总数不超过 30。
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- 每个结点的值不是 0 就是 1。
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## 解题思路
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- 给出一个链表，链表从头到尾表示的数是一个整数的二进制形式，要求输出这个整数的十进制。
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- 简单题，从头到尾遍历一次链表，边遍历边累加二进制位。
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## 代码
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```go
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func getDecimalValue(head *ListNode) int {
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sum := 0
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for head != nil {
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sum = sum*2 + head.Val
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head = head.Next
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}
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return sum
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}
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``` |