Spoj-BITDIFF Bit Difference

Given an integer array of N integers, find the sum of bit differences in all the pairs that can be formed from array elements. Bit difference of a pair (x, y) is the count of different bits at the same positions in binary representations of x and y. For example, bit difference for 2 and 7 is 2. Binary representation of 2 is 010 and 7 is 111 (first and last bits differ in two numbers).

Input

Input begins with a line containing an integer T(1<=T<=100), denoting the number of test cases. Then T test cases follow. Each test case begins with a line containing an integer N(1<=N<=10000), denoting the number of integers in the array, followed by a line containing N space separated 32-bit integers.

Output

For each test case, output a single line in the format Case X: Y, where X denotes the test case number and Y denotes the sum of bit differences in all the pairs that can be formed from array elements modulo 10000007.

Example

Input:
1
4
3 2 1 4

Output:
Case 1: 22

求和：对任意一对数(a,b)二进制展开，这两个数有多少位是01不同的

把每一位拆开来，假设第i位是1的有bit[i]个，答案就是Σ2*bit[i]*(n-bit[i])

#include<cstdio>
#include<iostream>
#include<cstring>
#include<cstdlib>
#include<algorithm>
#include<cmath>
#include<queue>
#include<deque>
#include<set>
#include<map>
#include<ctime>
#define LL long long
#define inf 0x7ffffff
#define pa pair<int,int>
#define mkp(a,b) make_pair(a,b)
#define pi 3.1415926535897932384626433832795028841971
#define mod 10000007
using namespace std;
inline LL read()
{
    LL x=0,f=1;char ch=getchar();
    while(ch<'0'||ch>'9'){if(ch=='-')f=-1;ch=getchar();}
    while(ch>='0'&&ch<='9'){x=x*10+ch-'0';ch=getchar();}
    return x*f;
}
int n;
LL ans;
int a[10010];
int bit[40];
inline void work(int cur)
{
    n=read();
    for (int i=1;i<=n;i++)a[i]=read();
    ans=0;
    memset(bit,0,sizeof(bit));
    for (int i=1;i<=n;i++)
        for (int j=0;j<=31;j++)
        if (a[i] & (1<<j))bit[j]++;
    for (int j=0;j<=31;j++)
        ans+=(LL)bit[j]*(n-bit[j])*2;
    printf("Case %d: %lld
",cur,ans%mod);
}
int main()
{
    int T=read(),tt=0;
    while (T--)work(++tt);
}