QOJ.ac
QOJ
ID | Problem | Submitter | Result | Time | Memory | Language | File size | Submit time | Judge time |
---|---|---|---|---|---|---|---|---|---|
#318009 | #7612. Matrix Inverse | nhuang685 | WA | 920ms | 35028kb | C++20 | 7.6kb | 2024-01-30 10:29:00 | 2024-01-30 10:29:01 |
Judging History
answer
/**
* @file qoj7612-1.cpp
* @author n685
* @brief
* @date 2024-01-29
*
*
*/
#include <bits/stdc++.h>
#ifdef LOCAL
#include "dd/debug.h"
#else
#define dbg(...) 42
#define dbgR(...) 4242
#define dbgP(...) 420
#define dbgRP(...) 420420
void nline() {}
#endif
template <class T> constexpr std::pair<T, T> exEucl(T a, T b) {
if (a < b) {
// auto [x, y] = exEucl(b, a);
T x, y;
std::tie(x, y) = exEucl(b, a);
return {y, x};
}
if (b == 0) {
assert(a == 1);
return {1, 0};
}
// auto [x, y] = exEucl(b, a % b);
T x, y;
std::tie(x, y) = exEucl(b, a % b);
return {y, x - (a / b) * y};
}
template <
class T, class U,
typename std::enable_if<std::is_integral<U>::value, bool>::type = true>
constexpr T binpow(T a, U b) {
// 0^0 = 1
T res = 1;
while (b > 0) {
if (b % 2 == 1) {
res *= a;
}
a *= a;
b /= 2;
}
return res;
}
template <class Md, class V = int64_t> struct Mod {
using T = typename std::decay<decltype(Md::value)>::type;
T val = 0;
template <class U> static constexpr T normalize(U val) {
if (val <= -Md::value || Md::value <= val) {
val %= Md::value;
}
if (val < 0) {
val += Md::value;
}
return static_cast<T>(val);
}
constexpr Mod() : val(0) {}
template <class U, typename std::enable_if<std::is_integral<U>::value,
bool>::type = true>
constexpr Mod(U _val) {
val = normalize(_val);
}
// addition
constexpr Mod &operator+=(Mod b) {
val += b.val;
if (val >= Md::value) {
val -= Md::value;
}
return *this;
}
friend constexpr Mod operator+(Mod a, Mod b) { return (a += b); }
constexpr Mod &operator++() { return (*this += 1); }
constexpr Mod operator++(int) {
Mod res = *this;
++(*this);
return res;
}
// subtraction
constexpr Mod &operator-=(Mod b) {
val -= b.val;
if (val < 0) {
val += Md::value;
}
return *this;
}
friend constexpr Mod operator-(Mod a, Mod b) { return (a -= b); }
constexpr Mod &operator--() { return (*this -= 1); }
constexpr Mod operator--(int) {
Mod res = *this;
--(*this);
return res;
}
// multiplication
constexpr Mod &operator*=(Mod b) {
val = static_cast<T>(static_cast<V>(val) * b.val % Md::value);
return *this;
}
friend constexpr Mod operator*(Mod a, Mod b) { return (a *= b); }
template <class U> constexpr Mod binpow(U b) const {
return ::binpow(*this, b);
}
constexpr Mod inv() const {
return Mod(exEucl(static_cast<V>(val), static_cast<V>(Md::value)).first);
// return binpow(Md::value - 2);
}
// comparison
constexpr bool operator==(Mod b) const { return (val == b.val); }
// constexpr auto operator<=>(const Mod &b) const = default;
constexpr bool operator!=(Mod b) const { return (val != b.val); }
constexpr bool operator<(Mod b) const { return (val < b.val); }
constexpr bool operator>(Mod b) const { return (val > b.val); }
constexpr bool operator<=(Mod b) const { return (val <= b.val); }
constexpr bool operator>=(Mod b) const { return (val >= b.val); }
// io
friend std::istream &operator>>(std::istream &in, Mod &a) {
V v;
in >> v;
a = Mod(v);
return in;
}
friend std::ostream &operator<<(std::ostream &out, const Mod &a) {
out << a.val;
return out;
}
// conversion
explicit constexpr operator T() const { return val; }
constexpr const T &operator()() const { return val; }
constexpr Mod operator-() const { return Mod(-val); }
};
constexpr int MOD = (int)1e9 + 7;
using Mint = Mod<std::integral_constant<std::decay<decltype(MOD)>::type, MOD>>;
using Row = std::vector<Mint>;
Row operator+=(Row &a, Row b) {
for (int i = 0; i < (int)a.size(); ++i) {
a[i] += b[i];
}
return a;
}
Row operator+(Row a, Row b) { return (a += b); }
Row operator-=(Row &a, Row b) {
for (int i = 0; i < (int)a.size(); ++i) {
a[i] -= b[i];
}
return a;
}
Row operator-(Row a, Row b) { return (a -= b); }
Row operator*=(Row &a, Mint b) {
for (int i = 0; i < (int)a.size(); ++i) {
a[i] *= b;
}
return a;
}
Row operator*(Row a, Mint b) { return a *= b; }
Row operator*(Mint b, Row a) { return a *= b; }
std::vector<Mint> gauss(std::vector<Row> eq) {
if ((int)eq.size() == 0) {
return {};
}
int n = (int)eq.size();
int m = (int)eq[0].size() - 1;
for (int i = 0; i < m; ++i) {
int ind = i;
while (ind < n && eq[ind][i] == 0) {
++ind;
}
if (ind == n) {
return {};
}
std::swap(eq[i], eq[ind]);
eq[i] *= eq[i][i].inv();
for (int j = 0; j < n; ++j) {
if (j != i) {
eq[j] -= eq[j][i] * eq[i];
}
}
}
std::vector<Mint> sol(m);
for (int i = 0; i < m; ++i) {
sol[i] = eq[i].back();
}
return sol;
}
int main() {
#ifdef LOCAL
std::freopen("input.txt", "r", stdin);
std::freopen("output.txt", "w", stdout);
#else
std::cin.tie(nullptr)->sync_with_stdio(false);
#endif
int n;
std::cin >> n;
std::vector a(n, std::vector<Mint>(n)), c(n, std::vector<Mint>(n));
for (int i = 0; i < n; ++i) {
for (int j = 0; j < n; ++j) {
std::cin >> a[i][j];
}
}
for (int i = 0; i < n; ++i) {
for (int j = 0; j < n; ++j) {
std::cin >> c[i][j];
}
}
std::mt19937 rng(std::chrono::steady_clock::now().time_since_epoch().count());
std::vector<int> r(n);
std::iota(r.begin(), r.end(), 0);
std::shuffle(r.begin(), r.end(), rng);
r.resize(std::min(n, 20));
std::vector<int> row, col;
for (int i = 0; i < n && (int)row.size() < 12; ++i) {
for (int j : r) {
Mint res = 0;
for (int k = 0; k < n; ++k) {
res += c[i][k] * a[k][j];
}
if (res != (i == j)) {
row.push_back(i);
break;
}
}
}
for (int i = 0; i < n && (int)col.size() < 12; ++i) {
for (int j : r) {
Mint res = 0;
for (int k = 0; k < n; ++k) {
res += a[i][k] * c[k][i];
}
if (res != (i == j)) {
col.push_back(i);
break;
}
}
}
const int m = (int)row.size() * (int)col.size();
// std::vector val(n, std::vector(n, Row(m + 1)));
// for (int i = 0; i < n; ++i) {
// for (int j = 0; j < n; ++j) {
// val[i][j].back() = c[i][j];
// }
// }
// for (int i = 0; i < (int)row.size(); ++i) {
// for (int j = 0; j < (int)col.size(); ++j) {
// val[row[i]][col[j]].back() = 0;
// val[row[i]][col[j]][(int)col.size() * i + j] = 1;
// }
// }
std::vector<Row> eq;
for (int i = 0; i < (int)col.size(); ++i) {
for (int j = 0; j < (int)r.size(); ++j) {
Row res(m + 1);
int ind = 0;
for (int k = 0; k < n; ++k) {
// res += a[r[j]][k] * val[k][i];
if (ind == (int)row.size() || k < row[ind]) {
res.back() += a[r[j]][k] * c[k][col[i]];
} else {
res[(int)col.size() * ind++ + i] += a[r[j]][k];
}
}
res.back() = (int)(r[j] == col[i]) - res.back();
eq.push_back(res);
}
}
std::vector<Mint> sol = gauss(eq);
std::vector<std::pair<std::pair<int, int>, Mint>> ans;
for (int i = 0; i < (int)row.size(); ++i) {
for (int j = 0; j < (int)col.size(); ++j) {
Mint v = sol[(int)col.size() * i + j];
if (c[row[i]][col[j]] != v) {
ans.emplace_back(std::pair{row[i], col[j]}, v);
}
}
}
std::cout << (int)ans.size() << '\n';
for (auto [aa, b] : ans) {
std::cout << aa.first + 1 << ' ' << aa.second + 1 << ' ' << b << '\n';
}
}
Details
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Test #1:
score: 100
Accepted
time: 0ms
memory: 3640kb
input:
1 953176428 107682094
output:
0
result:
ok single line: '0'
Test #2:
score: -100
Wrong Answer
time: 920ms
memory: 35028kb
input:
1995 586309310 548144807 578573993 437893403 641164340 712256053 172321263 108058526 768610920 123320669 762746291 856047593 979279376 29067913 309867338 292286426 45124325 239705174 675003623 213743652 620561338 116308277 695369179 669459894 682522334 846995555 159510341 999359657 645579085 7499563...
output:
0
result:
wrong answer 1st lines differ - expected: '2', found: '0'