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

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 ;
 }