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:heavy_check_mark: test/yosupo_system_of_linear_equations.test.cpp

Depends on

Code

#define PROBLEM "https://judge.yosupo.jp/problem/system_of_linear_equations"

#include <vector>
using namespace std;

static const int MOD = 998244353;
using ll = long long;
using uint = unsigned;
using ull = unsigned long long;

#include <cstdio>
#include <cstring>
#include <string>
#include <type_traits>

#include "../util/fastio.cpp"
#include "../math/gauss_jordan_mint.cpp"

int main() {
    Scanner in;
    Printer out;

    int n, m;
    in.read(n, m);
    vector<vector<mint>> a(n, vector<mint>(m + 1));
    for (int i = 0; i < n; ++i) {
        for (int j = 0; j < m; ++j) {
            int x;
            in.read(x);
            a[i][j] = x;
        }
    }
    for (int i = 0; i < n; ++i) {
        int x;
        in.read(x);
        a[i][m] = x;
    }

    int rank = gauss_jordan(a, true);
    for (int row = rank; row < n; ++row) {
        if (a[row][m].val) {
            out.println(-1);
            return 0;
        }
    }

    vector<int> pivot(rank, -1);
    vector<int> is_pivot(m);
    for (int row = 0; row < rank; ++row) {
        for (int col = 0; col < m; ++col) {
            if (a[row][col].val) {
                pivot[row] = col;
                is_pivot[col] = 1;
                break;
            }
        }
    }

    vector<mint> particular(m);
    for (int row = 0; row < rank; ++row) {
        particular[pivot[row]] = a[row][m];
    }

    vector<vector<mint>> basis;
    for (int free_col = 0; free_col < m; ++free_col) {
        if (is_pivot[free_col]) continue;
        vector<mint> vec(m);
        vec[free_col] = 1;
        for (int row = 0; row < rank; ++row) {
            vec[pivot[row]] = -a[row][free_col];
        }
        basis.push_back(vec);
    }

    out.println((int)basis.size());
    for (int i = 0; i < m; ++i) {
        out.print(particular[i].val);
        out.print(i + 1 == m ? '\n' : ' ');
    }
    for (auto &&vec : basis) {
        for (int i = 0; i < m; ++i) {
            out.print(vec[i].val);
            out.print(i + 1 == m ? '\n' : ' ');
        }
    }
    return 0;
}
#line 1 "test/yosupo_system_of_linear_equations.test.cpp"
#define PROBLEM "https://judge.yosupo.jp/problem/system_of_linear_equations"

#include <vector>
using namespace std;

static const int MOD = 998244353;
using ll = long long;
using uint = unsigned;
using ull = unsigned long long;

#include <cstdio>
#include <cstring>
#include <string>
#include <type_traits>

#line 1 "util/fastio.cpp"
using namespace std;

extern "C" int fileno(FILE *);
extern "C" int isatty(int);

template<class T, class = void>
struct is_fastio_range : false_type {};

template<class T>
struct is_fastio_range<T, void_t<decltype(declval<T &>().begin()), decltype(declval<T &>().end())>> : true_type {};

template<class T, class = void>
struct has_fastio_value : false_type {};

template<class T>
struct has_fastio_value<T, void_t<decltype(declval<const T &>().value())>> : true_type {};

struct FastIoDigitTable {
    char num[40000];

    constexpr FastIoDigitTable() : num() {
        for (int i = 0; i < 10000; ++i) {
            int x = i;
            for (int j = 3; j >= 0; --j) {
                num[i * 4 + j] = char('0' + x % 10);
                x /= 10;
            }
        }
    }
};

struct Scanner {
    static constexpr int BUFSIZE = 1 << 17;
    static constexpr int OFFSET = 64;
    char buf[BUFSIZE + 1];
    int idx, size;
    bool interactive;

    Scanner() : idx(0), size(0), interactive(isatty(fileno(stdin))) {}

    inline void load() {
        int len = size - idx;
        memmove(buf, buf + idx, len);
        if (interactive) {
            if (fgets(buf + len, BUFSIZE + 1 - len, stdin)) size = len + (int)strlen(buf + len);
            else size = len;
        } else {
            size = len + (int)fread(buf + len, 1, BUFSIZE - len, stdin);
        }
        idx = 0;
        buf[size] = 0;
    }

    inline void ensure() {
        if (idx + OFFSET > size) load();
    }

    inline void ensure_interactive() {
        if (idx == size) load();
    }

    inline char skip() {
        if (interactive) {
            ensure_interactive();
            while (buf[idx] && buf[idx] <= ' ') {
                ++idx;
                ensure_interactive();
            }
            return buf[idx++];
        }
        ensure();
        while (buf[idx] && buf[idx] <= ' ') {
            ++idx;
            ensure();
        }
        return buf[idx++];
    }

    template<class T, typename enable_if<is_integral<T>::value, int>::type = 0>
    void read(T &x) {
        if (interactive) {
            char c = skip();
            bool neg = false;
            if constexpr (is_signed<T>::value) {
                if (c == '-') {
                    neg = true;
                    ensure_interactive();
                    c = buf[idx++];
                }
            }
            x = 0;
            while (c >= '0') {
                x = x * 10 + (c & 15);
                ensure_interactive();
                c = buf[idx++];
            }
            if constexpr (is_signed<T>::value) {
                if (neg) x = -x;
            }
            return;
        }
        char c = skip();
        bool neg = false;
        if constexpr (is_signed<T>::value) {
            if (c == '-') {
                neg = true;
                c = buf[idx++];
            }
        }
        x = 0;
        while (c >= '0') {
            x = x * 10 + (c & 15);
            c = buf[idx++];
        }
        if constexpr (is_signed<T>::value) {
            if (neg) x = -x;
        }
    }

    template<class T, typename enable_if<!is_integral<T>::value && !is_fastio_range<T>::value && !is_same<typename decay<T>::type, string>::value && has_fastio_value<T>::value, int>::type = 0>
    void read(T &x) {
        long long v;
        read(v);
        x = T(v);
    }

    template<class Head, class Next, class... Tail>
    void read(Head &head, Next &next, Tail &...tail) {
        read(head);
        read(next, tail...);
    }

    template<class T, class U>
    void read(pair<T, U> &p) {
        read(p.first, p.second);
    }

    template<class T, typename enable_if<is_fastio_range<T>::value && !is_same<typename decay<T>::type, string>::value, int>::type = 0>
    void read(T &a) {
        for (auto &x : a) read(x);
    }

    void read(char &c) {
        c = skip();
    }

    void read(string &s) {
        s.clear();
        if (interactive) {
            ensure_interactive();
            while (buf[idx] && buf[idx] <= ' ') {
                ++idx;
                ensure_interactive();
            }
            while (true) {
                int start = idx;
                while (idx < size && buf[idx] > ' ') ++idx;
                s.append(buf + start, idx - start);
                if (idx < size) break;
                load();
                if (size == 0) break;
            }
            if (idx < size) ++idx;
            return;
        }
        ensure();
        while (buf[idx] && buf[idx] <= ' ') {
            ++idx;
            ensure();
        }
        while (true) {
            int start = idx;
            while (idx < size && buf[idx] > ' ') ++idx;
            s.append(buf + start, idx - start);
            if (idx < size) break;
            load();
        }
        if (idx < size) ++idx;
    }
};

struct Printer {
    static constexpr int BUFSIZE = 1 << 17;
    static constexpr int OFFSET = 64;
    char buf[BUFSIZE];
    int idx;
    bool interactive;
    inline static constexpr FastIoDigitTable table{};

    Printer() : idx(0), interactive(isatty(fileno(stdout))) {}
    ~Printer() { flush(); }

    inline void flush() {
        if (idx) {
            fwrite(buf, 1, idx, stdout);
            idx = 0;
        }
    }

    inline void pc(char c) {
        if (idx > BUFSIZE - OFFSET) flush();
        buf[idx++] = c;
        if (interactive && c == '\n') flush();
    }

    inline void print_range(const char *s, size_t n) {
        size_t pos = 0;
        while (pos < n) {
            if (idx == BUFSIZE) flush();
            size_t chunk = min(n - pos, (size_t)(BUFSIZE - idx));
            memcpy(buf + idx, s + pos, chunk);
            idx += (int)chunk;
            pos += chunk;
        }
    }

    void print(const char *s) {
        print_range(s, strlen(s));
    }

    void print(const string &s) {
        print_range(s.data(), s.size());
    }

    void print(char c) {
        pc(c);
    }

    void print(bool b) {
        pc(char('0' + (b ? 1 : 0)));
    }

    template<class T, typename enable_if<is_integral<T>::value && !is_same<T, bool>::value, int>::type = 0>
    void print(T x) {
        if (idx > BUFSIZE - 100) flush();
        using U = typename make_unsigned<T>::type;
        U y;
        if constexpr (is_signed<T>::value) {
            if (x < 0) {
                buf[idx++] = '-';
                y = U(0) - static_cast<U>(x);
            } else {
                y = static_cast<U>(x);
            }
        } else {
            y = x;
        }
        if (y == 0) {
            buf[idx++] = '0';
            return;
        }
        static constexpr int TMP_SIZE = sizeof(U) * 10 / 4;
        char tmp[TMP_SIZE];
        int pos = TMP_SIZE;
        while (y >= 10000) {
            pos -= 4;
            memcpy(tmp + pos, table.num + (y % 10000) * 4, 4);
            y /= 10000;
        }
        if (y >= 1000) {
            memcpy(buf + idx, table.num + (y << 2), 4);
            idx += 4;
        } else if (y >= 100) {
            memcpy(buf + idx, table.num + (y << 2) + 1, 3);
            idx += 3;
        } else if (y >= 10) {
            unsigned q = (unsigned(y) * 205) >> 11;
            buf[idx] = char('0' + q);
            buf[idx + 1] = char('0' + (unsigned(y) - q * 10));
            idx += 2;
        } else {
            buf[idx++] = char('0' + y);
        }
        memcpy(buf + idx, tmp + pos, TMP_SIZE - pos);
        idx += TMP_SIZE - pos;
    }

    template<class T, typename enable_if<!is_integral<T>::value && !is_fastio_range<T>::value && !is_same<typename decay<T>::type, string>::value && has_fastio_value<T>::value, int>::type = 0>
    void print(const T &x) {
        print(x.value());
    }

    template<class T, typename enable_if<is_fastio_range<T>::value && !is_same<typename decay<T>::type, string>::value, int>::type = 0>
    void print(const T &a) {
        bool first = true;
        for (auto &&x : a) {
            if (!first) pc(' ');
            first = false;
            print(x);
        }
    }

    template<class T>
    void println(const T &x) {
        print(x);
        pc('\n');
    }

    template<class Head, class... Tail>
    void println(const Head &head, const Tail &...tail) {
        print(head);
        ((pc(' '), print(tail)), ...);
        pc('\n');
    }

    void println() {
        pc('\n');
    }
};

template<class T>
Scanner &operator>>(Scanner &in, T &x) {
    in.read(x);
    return in;
}

template<class T>
Printer &operator<<(Printer &out, const T &x) {
    out.print(x);
    return out;
}

/**
 * @brief 高速入出力(Fast IO)
 */
#line 1 "util/modint.cpp"



template <uint Mod>
struct modint {
    uint val;
public:
    static modint raw(int v) { modint x; x.val = v; return x; }
    static constexpr uint get_mod() { return Mod; }
    static constexpr uint M() { return Mod; }
    modint() : val(0) {}
    template <class T>
    modint(T v) { ll x = (ll)(v % (ll)(Mod)); if (x < 0) x += Mod; val = uint(x); }
    modint(bool v) { val = ((unsigned int)(v) % Mod); }
    uint &value() noexcept { return val; }
    const uint &value() const noexcept { return val; }
    modint& operator++() { val++; if (val == Mod) val = 0; return *this; }
    modint& operator--() { if (val == 0) val = Mod; val--; return *this; }
    modint operator++(int) { modint result = *this; ++*this; return result; }
    modint operator--(int) { modint result = *this; --*this; return result; }
    modint& operator+=(const modint& b) { val += b.val; if (val >= Mod) val -= Mod; return *this; }
    modint& operator-=(const modint& b) { val -= b.val; if (val >= Mod) val += Mod; return *this; }
    modint& operator*=(const modint& b) { ull z = val; z *= b.val; val = (uint)(z % Mod); return *this; }
    modint& operator/=(const modint& b) { return *this = *this * b.inv(); }
    modint operator+() const { return *this; }
    modint operator-() const { return modint() - *this; }
    modint pow(long long n) const { modint x = *this, r = 1; while (n) { if (n & 1) r *= x; x *= x; n >>= 1; } return r; }
    modint inv() const { return pow(Mod - 2); }
    friend modint operator+(const modint& a, const modint& b) { return modint(a) += b; }
    friend modint operator-(const modint& a, const modint& b) { return modint(a) -= b; }
    friend modint operator*(const modint& a, const modint& b) { return modint(a) *= b; }
    friend modint operator/(const modint& a, const modint& b) { return modint(a) /= b; }
    friend bool operator==(const modint& a, const modint& b) { return a.val == b.val; }
    friend bool operator!=(const modint& a, const modint& b) { return a.val != b.val; }
};
using mint = modint<MOD>;
#define FIRIEXP_LIBRARY_MINT_ALIAS_DEFINED

/**
 * @brief modint(固定MOD)
 */


#line 2 "math/gauss_jordan_mint.cpp"

int gauss_jordan(vector<vector<mint>> &A, bool is_extended = false) {
    int m = A.size(), n = A[0].size();
    int rank = 0;
    for (int col = 0; col < n; ++col) {
        if (is_extended && col == n-1) break;
        int pivot = -1;
        for (int row = rank; row < m; ++row) {
            if (A[row][col].val) {
                pivot = row;
                break;
            }
        }
        if (pivot == -1) continue;
        swap(A[pivot], A[rank]);
        auto d = A[rank][col].inv();
        for (int col2 = 0; col2 < n; ++col2) A[rank][col2] *= d;
        for (int row = 0; row < m; ++row) {
            if (row != rank && A[row][col].val) {
                auto fac = A[row][col];
                for (int col2 = 0; col2 < n; ++col2) {
                    A[row][col2] -= A[rank][col2] * fac;
                }
            }
        }
        ++rank;
    }
    return rank;
}

/**
 * @brief Gauss-Jordan消去(modint)
 */
#line 18 "test/yosupo_system_of_linear_equations.test.cpp"

int main() {
    Scanner in;
    Printer out;

    int n, m;
    in.read(n, m);
    vector<vector<mint>> a(n, vector<mint>(m + 1));
    for (int i = 0; i < n; ++i) {
        for (int j = 0; j < m; ++j) {
            int x;
            in.read(x);
            a[i][j] = x;
        }
    }
    for (int i = 0; i < n; ++i) {
        int x;
        in.read(x);
        a[i][m] = x;
    }

    int rank = gauss_jordan(a, true);
    for (int row = rank; row < n; ++row) {
        if (a[row][m].val) {
            out.println(-1);
            return 0;
        }
    }

    vector<int> pivot(rank, -1);
    vector<int> is_pivot(m);
    for (int row = 0; row < rank; ++row) {
        for (int col = 0; col < m; ++col) {
            if (a[row][col].val) {
                pivot[row] = col;
                is_pivot[col] = 1;
                break;
            }
        }
    }

    vector<mint> particular(m);
    for (int row = 0; row < rank; ++row) {
        particular[pivot[row]] = a[row][m];
    }

    vector<vector<mint>> basis;
    for (int free_col = 0; free_col < m; ++free_col) {
        if (is_pivot[free_col]) continue;
        vector<mint> vec(m);
        vec[free_col] = 1;
        for (int row = 0; row < rank; ++row) {
            vec[pivot[row]] = -a[row][free_col];
        }
        basis.push_back(vec);
    }

    out.println((int)basis.size());
    for (int i = 0; i < m; ++i) {
        out.print(particular[i].val);
        out.print(i + 1 == m ? '\n' : ' ');
    }
    for (auto &&vec : basis) {
        for (int i = 0; i < m; ++i) {
            out.print(vec[i].val);
            out.print(i + 1 == m ? '\n' : ' ');
        }
    }
    return 0;
}
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