CF914G Sum the Fibonacci FWT、子集卷积

时间:2023-03-09 07:31:15
CF914G Sum the Fibonacci FWT、子集卷积

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一道良心的练习FWT和子集卷积的板子……

具体来说就是先把所有满足\(s_a \& s_b = 0\)的\(s_a \mid s_b\)的值用子集卷积算出来,将所有\(s_a \oplus s_b\)用xor卷积算出来,把斐波那契数代进去,然后将三个数组and卷积,最后取\(2^i (i \in Z)\)的位置的答案的和

#include<bits/stdc++.h>
//this code is written by Itst
using namespace std; int read(){
int a = 0; char c = getchar();
while(!isdigit(c)) c = getchar();
while(isdigit(c)){
a = a * 10 + c - 48;
c = getchar();
}
return a;
} const int _ = (1 << 17) + 3 , MOD = 1e9 + 7;
#define lowbit(x) (x & (-x))
int fib[_] , arr[_] , cnt1[_] , Or[18][_] , ansOr[_] , tmp[_] , And[_] , Xor[_] , N; void orFWT(int *arr , long long tp){
for(int i = 0 ; i < 17 ; ++i)
for(int j = 0 ; j < 1 << 17 ; j += 1 << (i + 1))
for(int k = 0 ; k < 1 << i ; ++k)
arr[(1 << i) + j + k] = (arr[(1 << i) + j + k] + tp * arr[j + k] + MOD) % MOD;
} void andFWT(int *arr , long long tp){
for(int i = 0 ; i < 17 ; ++i)
for(int j = 0 ; j < 1 << 17 ; j += 1 << (i + 1))
for(int k = 0 ; k < 1 << i ; ++k)
arr[j + k] = (arr[j + k] + tp * arr[(1 << i) + j + k] + MOD) % MOD;
} void xorFWT(int *arr , long long tp){
for(int i = 0 ; i < 17 ; ++i)
for(int j = 0 ; j < 1 << 17 ; j += 1 << (i + 1))
for(int k = 0 ; k < 1 << i ; ++k){
int x = arr[j + k] , y = arr[(1 << i) + j + k];
arr[j + k] = (x + y) % MOD;
arr[(1 << i) + j + k] = (x - y + MOD) % MOD;
if(tp == -1){
if(arr[j + k] & 1) arr[j + k] += MOD;
arr[j + k] >>= 1;
if(arr[(1 << i) + j + k] & 1) arr[(1 << i) + j + k] += MOD;
arr[(1 << i) + j + k] >>= 1;
}
}
} void init(){
for(int i = 1 ; i < 1 << 17 ; ++i)
cnt1[i] = cnt1[i - lowbit(i)] + 1;
fib[1] = 1;
for(int i = 2 ; i < 1 << 17 ; ++i)
fib[i] = (fib[i - 1] + fib[i - 2]) % MOD;
} int main(){
#ifndef ONLINE_JUDGE
freopen("in","r",stdin);
//freopen("out","w",stdout);
#endif
init();
N = read();
for(int i = 1 ; i <= N ; ++i){
int p = read();
++arr[p]; ++Or[cnt1[p]][p];
}
memcpy(And , arr , sizeof(arr)); memcpy(Xor , arr , sizeof(arr));
for(int i = 0 ; i <= 17 ; ++i)
orFWT(Or[i] , 1);
for(int i = 0 ; i <= 17 ; ++i){
memset(tmp , 0 , sizeof(tmp));
for(int j = 0 ; j <= i ; ++j)
for(int k = 0 ; k < 1 << 17 ; ++k)
tmp[k] = (tmp[k] + 1ll * Or[j][k] * Or[i - j][k]) % MOD;
orFWT(tmp , -1);
for(int k = 0 ; k < 1 << 17 ; ++k)
if(cnt1[k] == i)
ansOr[k] = tmp[k];
}
xorFWT(Xor , 1);
for(int i = 0 ; i < 1 << 17 ; ++i)
Xor[i] = 1ll * Xor[i] * Xor[i] % MOD;
xorFWT(Xor , -1);
for(int i = 0 ; i < 1 << 17 ; ++i){
ansOr[i] = 1ll * ansOr[i] * fib[i] % MOD;
And[i] = 1ll * And[i] * fib[i] % MOD;
Xor[i] = 1ll * Xor[i] * fib[i] % MOD;
}
andFWT(ansOr , 1); andFWT(And , 1); andFWT(Xor , 1);
for(int i = 0 ; i < 1 << 17 ; ++i)
And[i] = 1ll * ansOr[i] * And[i] % MOD * Xor[i] % MOD;
andFWT(And , -1);
int ans = 0;
for(int i = 1 ; i < 1 << 17 ; i <<= 1)
ans = (ans + And[i]) % MOD;
cout << ans;
return 0;
}