The 2018 ACM-ICPC Asia Qingdao Regional Contest K XOR Clique

BaoBao has a sequence a​1​​,a​2​​,...,a​n​​. He would like to find a subset S of {1,2,...,n} such that ∀i,j∈S, a​i​​⊕a​j​​<min(a​i​​,a​j​​) and ∣S∣ is maximum, where ⊕ means bitwise exclusive or.

Input

There are multiple test cases. The first line of input contains an integer T, indicating the number of test cases. For each test case:

The first line contains an integer n (1≤n≤10​5​​), indicating the length of the sequence.

The second line contains n integers: a​1​​,a​2​​,...,a​n​​ (1≤a​i​​≤10​9​​), indicating the sequence.

It is guaranteed that the sum of n in all cases does not exceed 10​5​​.

Output

For each test case, output an integer denoting the maximum size of S.

Sample Input

3

3

1 2 3

3

1 1 1

5

1 2323 534 534 5

Sample Output

2

3

2

给出n个数字，要求输出一个最长集合的长度，在这个集合中任意两个数两两异或后结果比原来小
相当于集合中每个数的二进制形式长度相等

 #include<bits/stdc++.h>

 using namespace std;

 int s[];

 int bit_width(unsigned int n)

 {

     unsigned int i = ;

     do {

         ++i;

     } while ((n >> i));

     return i;

 }

 int main()

 {

     int t;

     scanf("%d",&t);

     while(t--)

     {

         int n,a;

         scanf("%d",&n);

         memset(s,,sizeof(s));

         int len1,len2,num=,maxx=;

         for(int i=;i<n;i++)

         {

             scanf("%d",&a);

             len1=bit_width(a);

             s[len1]++;

         }

         for(int i=;i<;i++)

         {

             maxx=max(maxx,s[i]);

         }

         printf("%d\n",maxx);

     }

     return ;

 }