网络赛-青岛站-K XOR Clique

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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

 题目意思是找出个满足a​i​​⊕a​j​​<min(a​i​​,a​j​​)的集合且这个集合的元素最多，输出这个最多的值就是结果

我们在纸上画画就会发现，只有二进制位数相同的情况下才会满足情况，那么只有求出每一位的对应的元素数量，然后输出最大的数量就是答案

#include<bits/stdc++.h>
using namespace std;
int main()
{
	int t;
	scanf("%d", &t);
	while (t--)
	{
		int n;
		int a[100005]={0};
		scanf("%d", &n);
		int k=0;
		for (int i = 0; i < n; ++i)
		{
		    int x,sum=0;
			scanf("%d", &x);
			while(x)
			{
			    sum++;
			    x/=2;
			}
            a[sum]++;
		}
       for(int i=0;i<10000;i++)
       {
           k=max(k,a[i]);
       }
		printf("%d\n",k );
	}

}