异或和之和

https://ac.nowcoder.com/acm/contest/5600/J

#include<iostream>
using namespace std;
typedef long long ll;
const ll mod = 1e9+7;
const int maxn = 2e5+111;
int n;
ll k_qll a,ll b){
	ll res = 1;
	whileb){
		ifb&1){
			res = res*a)%mod;
		}
		b>>=1;
		a = a*a)%mod;
	}
	return res%mod;
}

ll jc[maxn];
ll list[maxn];//list[i]是i的阶乘
 
ll Cll n,ll m){

	ll ans = list[n]*jc[m]*jc[n - m])%mod))%mod;
	
	return ans%mod;
}

ll cnt1[2000];//1
ll cnt0[2000];

int main){
	scanf"%d",&n);
	list[0] = 1;
	
	forint i=1;i<maxn;i++){
		list[i] = 1LL*list[i-1] * i)%mod;
	}
	forint i=0;i<maxn;i++){
		jc[i] = k_qlist[i],mod-2)%mod;
	}
	
	int cns=0;
	forint i=0;i<n;i++){
		ll x;
		scanf"%lld",&x);
		forll j=0;j<60;j++){
			int t = x>>j)&1;
			ift) cnt1[j]++;
			else cnt0[j]++;
		}
	}
	ll sum = 0;
	ll ans = 0;
	forint i=0;i<60;i++){
		ifcnt1[i] == 0) continue;
	
		ifcnt1[i]>=3){
			ans = Ccnt1[i],3)*k_q2,i))%mod;
			
			sum = sum + ans)%mod;
			
		}
		ifcnt0[i] >= 2){
			
			ans = Ccnt0[i],2)*cnt1[i])%mod;
			
			ans = ans*k_q2,i))%mod;
			
			sum = sum + ans)%mod;
			
		}
	}
	cout<<sum<<endl;
	return 0;
} 

　　

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