We have an array A of non-negative integers.web
For every (contiguous) subarray B = [A[i], A[i+1], …, A[j]] (with i <= j), we take the bitwise OR of all the elements in B, obtaining a result A[i] | A[i+1] | … | A[j].数组
Return the number of possible results. (Results that occur more than once are only counted once in the final answer.)svg
Example 1:code
Input: [0] Output: 1 Explanation: There is only one possible result: 0.
Example 2:xml
Input: [1,1,2] Output: 3 Explanation: The possible subarrays are [1], [1], [2], [1, 1], [1, 2], [1, 1, 2]. These yield the results 1, 1, 2, 1, 3, 3. There are 3 unique values, so the answer is 3.
Example 3:ip
Input: [1,2,4] Output: 6 Explanation: The possible results are 1, 2, 3, 4, 6, and 7.
Note:element
题目的意思是:给定一个数组,求子数组的异或运算获得的值的数目。这里用三个set集合来计算,第一个set集合s用来保存最终的值,prev保存上一次遍历计算获得的异或值,t保存当前计算获得的异或值。而后遍历维护这三个集合就好了。leetcode
class Solution: def subarrayBitwiseORs(self, A: List[int]) -> int: s=set() prev=set() for x in A: t=set() for y in prev: t.add(x|y) t.add(x) prev=t s|=t return len(s)