#include <bits/stdc++.h> using namespace std; #define sim template < class c #define ris return * this #define dor > debug & operator << #define eni(x) sim > typename \ enable_if<sizeof dud<c>(0) x 1, debug&>::type operator<<(c i) { sim > struct rge { c b, e; }; sim > rge<c> range(c i, c j) { return rge<c>{i, j}; } sim > auto dud(c* x) -> decltype(cerr << *x, 0); sim > char dud(...); struct debug { #ifdef LOCAL ~debug() { cerr << endl; } eni(!=) cerr << boolalpha << i; ris; } eni(==) ris << range(begin(i), end(i)); } sim, class b dor(pair < b, c > d) { ris << "(" << d.first << ", " << d.second << ")"; } sim dor(rge<c> d) { *this << "["; for (auto it = d.b; it != d.e; ++it) *this << ", " + 2 * (it == d.b) << *it; ris << "]"; } #else sim dor(const c&) { ris; } #endif }; #define imie(...) " [" << #__VA_ARGS__ ": " << (__VA_ARGS__) << "] " // debug & operator << (debug & dd, P p) { dd << "(" << p.x << ", " << p.y << ")"; return dd; } const int MOD = 1e9 + 7; int mul(int a, int b) { return (long long) a * b % MOD; } int my_pow(int a, int b) { int r = 1; while (b) { if (b % 2) { r = mul(r, a); } a = mul(a, a); b /= 2; } return r; } int my_inv(int a) { return my_pow(a, MOD - 2); } void gauss(vector<vector<int>> a) { int n = a.size(); assert((int) a[0].size() == n); for (int col = 0; col < n; col++) { // cerr << col << " "; for (int sr = col; sr < n; sr++) { if (a[sr][col]) { int row = col; swap(a[sr], a[row]); int inv = my_inv(a[row][row]); for (int r2 = row + 1; r2 < n; r2++) { int x = mul(inv, a[r2][col]); for (int j = col; j < n; j++) { a[r2][j] = (a[r2][j] - mul(x, a[row][j]) + MOD) % MOD; } } } } } for (vector<int> row : a) { debug() << row; } int product = 1; for (int i = 0; i < n; i++) { product = mul(product, a[i][i]); } debug() << imie(product); printf("%d\n", product); } int main() { int n; scanf("%d", &n); if (n == 1) { puts("1"); return 0; } vector<int> a(n); for (int i = 0; i < n; i++) { scanf("%d", &a[i]); } vector<vector<int>> grid(n-1, vector<int>(n-1)); for (int i = 0; i < n - 1; i++) { for (int j = 0; j < n - 1; j++) { if (i != j) { grid[i][j] = MOD - __gcd(a[i], a[j]); } else { for (int z = 0; z < n; z++) { if (z != i) { grid[i][i] += __gcd(a[i], a[z]); } } } } } gauss(grid); // vector<vector<int>> grid; // grid.push_back({3,MOD-1,MOD-1}); // grid.push_back({MOD-1,3,MOD-1}); // grid.push_back({-1,-1,2}); // gauss(grid); }
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 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 | #include <bits/stdc++.h> using namespace std; #define sim template < class c #define ris return * this #define dor > debug & operator << #define eni(x) sim > typename \ enable_if<sizeof dud<c>(0) x 1, debug&>::type operator<<(c i) { sim > struct rge { c b, e; }; sim > rge<c> range(c i, c j) { return rge<c>{i, j}; } sim > auto dud(c* x) -> decltype(cerr << *x, 0); sim > char dud(...); struct debug { #ifdef LOCAL ~debug() { cerr << endl; } eni(!=) cerr << boolalpha << i; ris; } eni(==) ris << range(begin(i), end(i)); } sim, class b dor(pair < b, c > d) { ris << "(" << d.first << ", " << d.second << ")"; } sim dor(rge<c> d) { *this << "["; for (auto it = d.b; it != d.e; ++it) *this << ", " + 2 * (it == d.b) << *it; ris << "]"; } #else sim dor(const c&) { ris; } #endif }; #define imie(...) " [" << #__VA_ARGS__ ": " << (__VA_ARGS__) << "] " // debug & operator << (debug & dd, P p) { dd << "(" << p.x << ", " << p.y << ")"; return dd; } const int MOD = 1e9 + 7; int mul(int a, int b) { return (long long) a * b % MOD; } int my_pow(int a, int b) { int r = 1; while (b) { if (b % 2) { r = mul(r, a); } a = mul(a, a); b /= 2; } return r; } int my_inv(int a) { return my_pow(a, MOD - 2); } void gauss(vector<vector<int>> a) { int n = a.size(); assert((int) a[0].size() == n); for (int col = 0; col < n; col++) { // cerr << col << " "; for (int sr = col; sr < n; sr++) { if (a[sr][col]) { int row = col; swap(a[sr], a[row]); int inv = my_inv(a[row][row]); for (int r2 = row + 1; r2 < n; r2++) { int x = mul(inv, a[r2][col]); for (int j = col; j < n; j++) { a[r2][j] = (a[r2][j] - mul(x, a[row][j]) + MOD) % MOD; } } } } } for (vector<int> row : a) { debug() << row; } int product = 1; for (int i = 0; i < n; i++) { product = mul(product, a[i][i]); } debug() << imie(product); printf("%d\n", product); } int main() { int n; scanf("%d", &n); if (n == 1) { puts("1"); return 0; } vector<int> a(n); for (int i = 0; i < n; i++) { scanf("%d", &a[i]); } vector<vector<int>> grid(n-1, vector<int>(n-1)); for (int i = 0; i < n - 1; i++) { for (int j = 0; j < n - 1; j++) { if (i != j) { grid[i][j] = MOD - __gcd(a[i], a[j]); } else { for (int z = 0; z < n; z++) { if (z != i) { grid[i][i] += __gcd(a[i], a[z]); } } } } } gauss(grid); // vector<vector<int>> grid; // grid.push_back({3,MOD-1,MOD-1}); // grid.push_back({MOD-1,3,MOD-1}); // grid.push_back({-1,-1,2}); // gauss(grid); } |