#include <bits/stdc++.h> using namespace std; typedef pair<int,int> PII; typedef pair<int,long long> PIL; const int mod = 1e9+7; int nwd(int a, int b){ if(b == 0) return a; return nwd(b, a%b); } long long pot(long long a, int x){ if(x == 0) return 1; if(x&1) return pot(a, x-1)*a%mod; long long tmp = pot(a, x/2); return tmp*tmp%mod; } #define mp make_pair #define pb push_back #define x first #define y second #define rep(i,b,e) for(int i=(b); i<(e); i++) #define each(a,x) for(auto& a : (x)) #define all(x) (x).begin(),(x).end() #define sz(x) int((x).size()) using Row = vector<long long>; using Matrix = vector<Row>; // copied for jagiellonian algolib int echelon(Matrix& A, int& sign) { // O(nˆ3) int rank = 0; sign = 1; rep(c, 0, sz(A[0])) { if (rank >= sz(A)) break; rep(i, rank+1, sz(A)) if (A[i][c]) { swap(A[i], A[rank]); sign *= -1; break; } // f98a if (A[rank][c]) { rep(i, rank+1, sz(A)) { long long mult = (A[i][c] * pot(A[rank][c], mod-2))%mod; rep(j, 0, sz(A[0])) A[i][j] = (A[i][j]-A[rank][j]*mult)%mod; } // f519 rank++; } // 4cd8 //cout<<"c "<<c<<endl; } // 36e9 return rank; } long long det(Matrix A) { int s; echelon(A, s); long long ret = s; rep(i, 0, sz(A)) ret = (ret*A[i][i])%mod; if(ret < 0) ret += mod; return ret; } // b252 int arr[5005]; int main(){ ios_base::sync_with_stdio(0); int n; cin>>n; Matrix A(n); for(int i=0;i<n;i++) cin>>arr[i]; for(int i=0;i<n;i++) for(int j=0;j<n;j++){ A[i].push_back(nwd(arr[i], arr[j])); } if(n == 1){ cout<<1<<endl; return 0; } for(int i=0;i<n;i++){ int sum = 0; for(int j=0;j<n;j++){ sum += A[i][j]; A[i][j] = -A[i][j]; } A[i][i] += sum; } for(int i=0;i<n;i++) A[i].pop_back(); A.pop_back(); cout<<det(A)<<endl; }
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 | #include <bits/stdc++.h> using namespace std; typedef pair<int,int> PII; typedef pair<int,long long> PIL; const int mod = 1e9+7; int nwd(int a, int b){ if(b == 0) return a; return nwd(b, a%b); } long long pot(long long a, int x){ if(x == 0) return 1; if(x&1) return pot(a, x-1)*a%mod; long long tmp = pot(a, x/2); return tmp*tmp%mod; } #define mp make_pair #define pb push_back #define x first #define y second #define rep(i,b,e) for(int i=(b); i<(e); i++) #define each(a,x) for(auto& a : (x)) #define all(x) (x).begin(),(x).end() #define sz(x) int((x).size()) using Row = vector<long long>; using Matrix = vector<Row>; // copied for jagiellonian algolib int echelon(Matrix& A, int& sign) { // O(nˆ3) int rank = 0; sign = 1; rep(c, 0, sz(A[0])) { if (rank >= sz(A)) break; rep(i, rank+1, sz(A)) if (A[i][c]) { swap(A[i], A[rank]); sign *= -1; break; } // f98a if (A[rank][c]) { rep(i, rank+1, sz(A)) { long long mult = (A[i][c] * pot(A[rank][c], mod-2))%mod; rep(j, 0, sz(A[0])) A[i][j] = (A[i][j]-A[rank][j]*mult)%mod; } // f519 rank++; } // 4cd8 //cout<<"c "<<c<<endl; } // 36e9 return rank; } long long det(Matrix A) { int s; echelon(A, s); long long ret = s; rep(i, 0, sz(A)) ret = (ret*A[i][i])%mod; if(ret < 0) ret += mod; return ret; } // b252 int arr[5005]; int main(){ ios_base::sync_with_stdio(0); int n; cin>>n; Matrix A(n); for(int i=0;i<n;i++) cin>>arr[i]; for(int i=0;i<n;i++) for(int j=0;j<n;j++){ A[i].push_back(nwd(arr[i], arr[j])); } if(n == 1){ cout<<1<<endl; return 0; } for(int i=0;i<n;i++){ int sum = 0; for(int j=0;j<n;j++){ sum += A[i][j]; A[i][j] = -A[i][j]; } A[i][i] += sum; } for(int i=0;i<n;i++) A[i].pop_back(); A.pop_back(); cout<<det(A)<<endl; } |