Benny and Queries

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43 votes
Trie, Approved, Medium-Hard, Greedy algorithm
Problem

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Probably, you have already read some problems but you still have not met any problems with queries on segments. Therefore Benny wants to fix it.

She gives you an array A of N elements. And then you have to answer Q queries.

Each query consists of three integers L, R, X. Your task is to find such Ai, that LiR and Ai xor X is maximal. For each query output the maximum of Ai xor X.

Input format

The first line contains two integers N and Q. The next line contains N integers Ai. The next Q lines contain three integers L, R, X.

Output format

For each query output the maximum of Ai xor X in a single line.

Constraints

  • 1 ≤ N, Q ≤ 5 * 105
  • 0 ≤ Ai < 220
  • 1 ≤ L ≤ R ≤ N
  • 0 ≤ X < 220
  • 1 ≤ N, Q ≤ 3 * 103 holds for test cases worth 15% of the problem's score.
  • 1 ≤ N, Q ≤ 105 holds for test cases worth 60% of the problem's score.
Time Limit: 4
Memory Limit: 512
Source Limit:
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