Language: C++

#pragma GCC optimize ("O3")
#pragma GCC target ("avx")
#include "bits/stdc++.h"
 
using namespace std;
using ll = long long int;
 
#define debug(v) {printf("L%d %s > ",__LINE__,#v);cout<<(v)<<endl;}
#define debugv(v) {printf("L%d %s > ",__LINE__,#v);for(auto e:(v)){cout<<e<<" ";}cout<<endl;}
#define debuga(m,w) {printf("L%d %s > ",__LINE__,#m);for(int x=0;x<(w);x++){cout<<(m)[x]<<" ";}cout<<endl;}
#define debugaa(m,h,w) {printf("L%d %s >\n",__LINE__,#m);for(int y=0;y<(h);y++){for(int x=0;x<(w);x++){cout<<(m)[y][x]<<" ";}cout<<endl;}}
#define ALL(v) (v).begin(),(v).end()
#define repeat(cnt,l) for(remove_const<decltype(l)>::type cnt=0;(cnt)<(l);++(cnt))
#define rrepeat(cnt,l) for(auto cnt=(l)-1;0<=(cnt);--(cnt))
#define iterate(cnt,b,e) for(auto cnt=(b);(cnt)!=(e);++(cnt))
#define diterate(cnt,b,e) for(auto cnt=(b);(cnt)!=(e);--(cnt))
const ll MD = 1000000007ll; const long double PI = 3.1415926535897932384626433832795L;
template<typename T1, typename T2> inline void assert_equal(T1 expected, T2 actual) { if (!(expected == actual)) { cerr << "assertion fault: expected=" << expected << " actual=" << actual << endl; abort(); } }
template<typename T1, typename T2> inline void assert_less(T1 actual, T2 threshold) { if (!(actual < threshold)) { cerr << "assertion fault: " << actual << " < (const)" << threshold << endl; abort(); } }
template<typename T1, typename T2> inline void assert_eqless(T1 actual, T2 threshold) { if (!(actual <= threshold)) { cerr << "assertion fault: " << actual << " <= (const)" << threshold << endl; abort(); } }
template<typename T1, typename T2> inline ostream& operator <<(ostream &o, const pair<T1, T2> p) { o << '(' << p.first << ':' << p.second << ')'; return o; }
template<typename Vec> inline ostream& _ostream_vecprint(ostream &o, const Vec& p) { o << '['; for (auto& e : p) o << e << ','; o << ']'; return o; }
template<typename T> inline ostream& operator<<(ostream& o, const vector<T>& v) { return _ostream_vecprint(o, v); }
template<typename T, size_t S> inline ostream& operator<<(ostream& o, const array<T, S>& v) { return _ostream_vecprint(o, v); }
template<typename T> inline T& maxset(T& to, const T& val) { return to = max(to, val); }
template<typename T> inline T& minset(T& to, const T& val) { return to = min(to, val); }
void bye(string s, int code = 0) { cout << s << endl; exit(code); }
mt19937_64 randdev(8901016);
template<typename T> inline T rand(T l, T h) { return uniform_int_distribution<T>(l, h)(randdev); }
template<> inline double rand<double>(double l, double h) { return uniform_real_distribution<double>(l, h)(randdev); }
template<> inline float rand<float>(float l, float h) { return uniform_real_distribution<float>(l, h)(randdev); }
 
#if defined(_WIN32) || defined(_WIN64)
#define getchar_unlocked _getchar_nolock
#define putchar_unlocked _putchar_nolock
#elif defined(__GNUC__)
#else
#define getchar_unlocked getchar
#define putchar_unlocked putchar
#endif
namespace {
#define isvisiblechar(c) (0x21<=(c)&&(c)<=0x7E)
    class MaiScanner {
    public:
        template<typename T> void input_integer(T& var) {
            var = 0; T sign = 1;
            int cc = getchar_unlocked();
            for (; cc<'0' || '9'<cc; cc = getchar_unlocked())
                if (cc == '-') sign = -1;
            for (; '0' <= cc && cc <= '9'; cc = getchar_unlocked())
                var = (var << 3) + (var << 1) + cc - '0';
            var = var * sign;
        }
        inline int c() { return getchar_unlocked(); }
        inline MaiScanner& operator>>(int& var) { input_integer<int>(var); return *this; }
        inline MaiScanner& operator>>(long long& var) { input_integer<long long>(var); return *this; }
        inline MaiScanner& operator>>(string& var) {
            int cc = getchar_unlocked();
            for (; !isvisiblechar(cc); cc = getchar_unlocked());
            for (; isvisiblechar(cc); cc = getchar_unlocked())
                var.push_back(cc);
            return *this;
        }
        template<typename IT> void in(IT begin, IT end) { for (auto it = begin; it != end; ++it) *this >> *it; }
    };
    class MaiPrinter {
    public:
        template<typename T>
        void output_integer(T var) {
            if (var == 0) { putchar_unlocked('0'); return; }
            if (var < 0)
                putchar_unlocked('-'),
                var = -var;
            char stack[32]; int stack_p = 0;
            while (var)
                stack[stack_p++] = '0' + (var % 10),
                var /= 10;
            while (stack_p)
                putchar_unlocked(stack[--stack_p]);
        }
        inline MaiPrinter& operator<<(char c) { putchar_unlocked(c); return *this; }
        inline MaiPrinter& operator<<(int var) { output_integer<int>(var); return *this; }
        inline MaiPrinter& operator<<(long long var) { output_integer<long long>(var); return *this; }
        inline MaiPrinter& operator<<(char* str_p) { while (*str_p) putchar_unlocked(*(str_p++)); return *this; }
        inline MaiPrinter& operator<<(const string& str) {
            const char* p = str.c_str();
            const char* l = p + str.size();
            while (p < l) putchar_unlocked(*p++);
            return *this;
        }
        template<typename IT> void join(IT begin, IT end, char sep = '\n') { for (auto it = begin; it != end; ++it) *this << *it << sep; }
    };
}
MaiScanner scanner;
MaiPrinter printer;


class DGraphF {
public:
    typedef int cap_t;
    size_t n_;
    struct Arc {
        int from, to;
        // 残量
        cap_t left;
        // 容量
        cap_t cap;

        Arc(int from = 0, int to = 0, cap_t w = 1) :from(from), to(to), left(w), cap(w) {}
        inline bool operator<(const Arc& a) const { return (left != a.left) ? left < a.left : (left<a.left) | (cap<a.cap) | (from<a.from) | (to<a.to); }
        inline bool operator==(const Arc& a) const { return (from == a.from) && (to == a.to) && (left == a.left) && (cap == a.cap); }
    };
    vector<vector<int>> vertex_to;
    vector<vector<int>> vertex_from;
    vector<Arc> edges;

    DGraphF(int n = 1) :n_(n), vertex_to(n), vertex_from(n) { }

    void connect(int from, int to, cap_t left) {
        vertex_to[(size_t)from].push_back((int)edges.size()); // toto
        vertex_from[(size_t)to].push_back((int)edges.size()); // fromfrom
        edges.emplace_back(from, to, left);
    }
};


void dinic(DGraphF &graph, vector<DGraphF::cap_t>& result, int i_source, int i_sink) {
    assert(i_source != i_sink);

    result.resize(graph.n_);
    vector<int> dist(graph.n_);
    queue<int> q;
    vector<int> flag(graph.n_);

    static function<DGraphF::cap_t(int, int, DGraphF::cap_t)> _dfs = [&](int u, int i_sink, DGraphF::cap_t mini) {
        // DAG
        // TODO: 経路再利用
        if (i_sink == u) return mini;
        if (flag[u]) return (DGraphF::cap_t) - 1;
        flag[u] = true;

        DGraphF::cap_t sumw = 0;
        bool term = true;
        for (int e : graph.vertex_to[u]) {
            auto& edge = graph.edges[e];
            if (edge.left > 0 && dist[u]>dist[edge.to]) {
                DGraphF::cap_t w = (mini < 0) ? edge.left : min(edge.left, mini);

                w = _dfs(edge.to, i_sink, w);
                if (w == -1) continue;
                edge.left -= w;
                result[edge.to] += w;

                sumw += w;
                mini -= w;
                term = false;
                flag[u] = false; // TODO: 末尾では? 

                if (mini == 0) return sumw;
            }
        }
        for (int e : graph.vertex_from[u]) {
            auto& edge = graph.edges[e];
            if (edge.cap>edge.left && dist[u]>dist[edge.from]) {
                DGraphF::cap_t w = (mini < 0) ? (edge.cap - edge.left) : min(edge.cap - edge.left, mini);

                w = _dfs(edge.from, i_sink, w);
                if (w == -1) continue;
                edge.left += w;
                result[edge.to] -= w;

                sumw += w;
                mini -= w;
                term = false;
                flag[u] = false;
                if (mini == 0) return sumw;
            }
        }
        return term ? (DGraphF::cap_t)(-1) : sumw;
    };


    for (int distbegin = 0; ; distbegin += (int)graph.n_) {

        q.emplace(i_sink); // bfsはsinkからsourceへの距離を計算．
        dist[i_sink] = distbegin + 1;
        while (!q.empty()) {
            int v = q.front();
            q.pop();
            for (int ie : graph.vertex_from[v]) {
                const auto edge = graph.edges[ie];
                if (0 < edge.left && dist[edge.from] <= distbegin) {
                    dist[edge.from] = dist[v] + 1;
                    q.emplace(edge.from);
                }
            }
            for (int ie : graph.vertex_to[v]) {
                const auto edge = graph.edges[ie];
                if (edge.left < edge.cap && dist[edge.to] <= distbegin) {
                    dist[edge.to] = dist[v] + 1;
                    q.emplace(edge.to);
                }
            }
        }
        fill(flag.begin(), flag.end(), false);

        if (dist[i_source] <= distbegin)
            break;
        else
            result[i_source] += _dfs(i_source, i_sink, -1);
    }
}


int main(){
    int blue[555],red[555];
    
    int m,n;
    while(scanner >> m >> n, m != 0 || n != 0){
        DGraphF g(m+n+2);
        const int vs = m+n, vt = m+n+1;
        scanner.in(blue,blue+m);
        scanner.in(red,red+n);
        repeat(i, m)
            repeat(j, n)
                if (gcd(blue[i],red[j])>1) g.connect(i,m+j,1);
        repeat(i,m)
            g.connect(v_s,i,1);
        repeat(j,n)
            g.connect(v_t,j,1);
        
        vector<int> f;
        dinic(g,f,vs,vt);
        printer << f[vt] << '\n';
    }
    return 0;
}


Compiler output:
a.cc: In function 'int main()':
a.cc:228:23: error: 'v_s' was not declared in this scope; did you mean 'vs'?
  228 |             g.connect(v_s,i,1);
      |                       ^~~
      |                       vs
a.cc:230:23: error: 'v_t' was not declared in this scope; did you mean 'vt'?
  230 |             g.connect(v_t,j,1);
      |                       ^~~
      |                       vt