CF1979B.XOR Sequences

传统题 时间 2000 ms 内存 256 MiB 5 尝试 1 已通过 1 标签

XOR Sequences

You are given two distinct non-negative integers xx and yy. Consider two infinite sequences a1,a2,a3,a_1, a_2, a_3, \ldots and b1,b2,b3,b_1, b_2, b_3, \ldots, where

  • an=nxa_n = n \oplus x;
  • bn=nyb_n = n \oplus y.

Here, xyx \oplus y denotes the bitwise XOR operation of integers xx and yy.

For example, with x=6x = 6, the first 88 elements of sequence aa will look as follows: [7,4,5,2,3,0,1,14,][7, 4, 5, 2, 3, 0, 1, 14, \ldots]. Note that the indices of elements start with 11.

Your task is to find the length of the longest common subsegment^\dagger of sequences aa and bb. In other words, find the maximum integer mm such that $a_i = b_j, a_{i + 1} = b_{j + 1}, \ldots, a_{i + m - 1} = b_{j + m - 1}$ for some i,j1i, j \ge 1.

^\daggerA subsegment of sequence pp is a sequence pl,pl+1,,prp_l,p_{l+1},\ldots,p_r, where 1lr1 \le l \le r.

Input

Each test consists of multiple test cases. The first line contains a single integer tt (1t1041 \le t \le 10^4) — the number of test cases. The description of the test cases follows.

The only line of each test case contains two integers xx and yy (0x,y109,xy0 \le x, y \le 10^9, x \neq y) — the parameters of the sequences.

Output

For each test case, output a single integer — the length of the longest common subsegment.

Note

In the first test case, the first 77 elements of sequences aa and bb are as follows:

a=[1,2,3,4,5,6,7,]a = [1, 2, 3, 4, 5, 6, 7,\ldots] b=[0,3,2,5,4,7,6,]b = [0, 3, 2, 5, 4, 7, 6,\ldots]

It can be shown that there isn't a positive integer kk such that the sequence [k,k+1][k, k + 1] occurs in bb as a subsegment. So the answer is 11.

In the third test case, the first 2020 elements of sequences aa and bb are as follows:

$$a = [56, 59, 58, 61, 60, 63, 62, 49, 48, 51, 50, 53, 52, 55, 54, \textbf{41, 40, 43, 42}, 45, \ldots]$$$$b = [36, 39, 38, 33, 32, 35, 34, 45, 44, 47, 46, \textbf{41, 40, 43, 42}, 53, 52, 55, 54, 49, \ldots]$$

It can be shown that one of the longest common subsegments is the subsegment [41,40,43,42][41, 40, 43, 42] with a length of 44.

Samples

4
0 1
12 4
57 37
316560849 14570961
1
8
4
33554432

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