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1720.decode-xored-array

Statement

Metadata

未知 整数数组 arrn 个非负整数组成。

经编码后变为长度为 n - 1 的另一个整数数组 encoded ,其中 encoded[i] = arr[i] XOR arr[i + 1] 。例如,arr = [1,0,2,1] 经编码后得到 encoded = [1,2,3]

给你编码后的数组 encoded 和原数组 arr 的第一个元素 firstarr[0])。

请解码返回原数组 arr 。可以证明答案存在并且是唯一的。

 

示例 1:

输入:encoded = [1,2,3], first = 1
输出:[1,0,2,1]
解释:若 arr = [1,0,2,1] ,那么 first = 1 且 encoded = [1 XOR 0, 0 XOR 2, 2 XOR 1] = [1,2,3]

示例 2:

输入:encoded = [6,2,7,3], first = 4
输出:[4,2,0,7,4]

 

提示:

  • 2 <= n <= 104
  • encoded.length == n - 1
  • 0 <= encoded[i] <= 105
  • 0 <= first <= 105

Metadata

There is a hidden integer array arr that consists of n non-negative integers.

It was encoded into another integer array encoded of length n - 1, such that encoded[i] = arr[i] XOR arr[i + 1]. For example, if arr = [1,0,2,1], then encoded = [1,2,3].

You are given the encoded array. You are also given an integer first, that is the first element of arr, i.e. arr[0].

Return the original array arr. It can be proved that the answer exists and is unique.

 

Example 1:

Input: encoded = [1,2,3], first = 1
Output: [1,0,2,1]
Explanation: If arr = [1,0,2,1], then first = 1 and encoded = [1 XOR 0, 0 XOR 2, 2 XOR 1] = [1,2,3]

Example 2:

Input: encoded = [6,2,7,3], first = 4
Output: [4,2,0,7,4]

 

Constraints:

  • 2 <= n <= 104
  • encoded.length == n - 1
  • 0 <= encoded[i] <= 105
  • 0 <= first <= 105

Solution

from typing import List


class Solution:
    def decode(self, encoded: List[int], first: int) -> List[int]:
        res = [first]
        for x in encoded:
            res.append(x ^ res[-1])
        return res

最后更新: October 11, 2023
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