J.cpp

#include <bits/stdc++.h>
#define int long long
#define FOR(i,a,b) for(int i=(a),_b=(b); i<=_b; ++i)
#define FORD(i,a,b) for(int i=(a),_b=(b); i>=_b; --i)
#define REP(i,a) for(int i=0,_a=(a); i < _a; ++i)

#define DEBUG(X) { cout << #X << " = " << (X) << endl; }
#define PR(A,n)  { cout << #A << " = "; FOR(_,1,n) cout << A[_] << ' '; cout << endl; }
#define PR0(A,n) { cout << #A << " = "; REP(_,n) cout << A[_] << ' '; cout << endl; }

#define sqr(x) ((x) * (x))
#define ll long long
#define __builtin_popcount __builtin_popcountll
#define SZ(x) ((int) (x).size())
using namespace std;

double safe_sqrt(double x) {
    return sqrt(max((double)0.0,x));
}
int GI(ll& x) {
    return scanf("%lld", &x);
}
#define EPS 1e-6
const double PI = acos(-1.0);

double DEG_to_RAD(double d) { return d * PI / 180.0; }
double RAD_to_DEG(double r) { return r * 180.0 / PI; }

inline int cmp(double a, double b) {
    return (a < b - EPS) ? -1 : ((a > b + EPS) ? 1 : 0);
}

struct Point {
    double x, y;
    Point(double x = 0.0, double y = 0.0) : x(x), y(y) {}

    Point operator + (const Point& a) const { return Point(x+a.x, y+a.y); }
    Point operator - (const Point& a) const { return Point(x-a.x, y-a.y); }
    Point operator * (double k) const { return Point(x*k, y*k); }
    Point operator / (double k) const { return Point(x/k, y/k); }

    double operator * (const Point& a) const { return x*a.x + y*a.y; } // dot product
    double operator % (const Point& a) const { return x*a.y - y*a.x; } // cross product

    int cmp(Point q) const { if (int t = ::cmp(x,q.x)) return t; return ::cmp(y,q.y); }

    #define Comp(x) bool operator x (Point q) const { return cmp(q) x 0; }
    Comp(>) Comp(<) Comp(==) Comp(>=) Comp(<=) Comp(!=)
    #undef Comp

    Point conj() { return Point(x, -y); }
    double norm() { return x*x + y*y; }

    // Note: There are 2 ways for implementing len():
    // 1. sqrt(norm()) --> fast, but inaccurate (produce some values that are of order X^2)
    // 2. hypot(x, y) --> slow, but much more accurate
    double len() { return sqrt(norm()); }

    Point rotate(double alpha) {
        double cosa = cos(alpha), sina = sin(alpha);
        return Point(x * cosa - y * sina, x * sina + y * cosa);
    }
};

int ccw(Point a, Point b, Point c) {
    return cmp((b-a)%(c-a),0);
}
int RE_TRAI = ccw(Point(0, 0), Point(0, 1), Point(-1, 1));
int RE_PHAI = ccw(Point(0, 0), Point(0, 1), Point(1, 1));
istream& operator >> (istream& cin, Point& p) {
    cin >> p.x >> p.y;
    return cin;
}
ostream& operator << (ostream& cout, Point& p) {
    cout << p.x << ' ' << p.y;
    return cout;
}
typedef vector< Point > Polygon;
#define Det(a,b,c) ((double)(b.x-a.x)*(double)(c.y-a.y)-(double)(b.y-a.y)*(c.x-a.x))
bool in_convex(vector<Point>& l, Point p){
    int a = 1, b = l.size()-1, c;
    if (Det(l[0], l[a], l[b]) > 0) swap(a,b);
    // Allow on edge --> if (Det... > 0 || Det ... < 0)
    if (Det(l[0], l[a], p) >= 0 || Det(l[0], l[b], p) <= 0) return false;
    while(abs(a-b) > 1) {
        c = (a+b)/2;
        if (Det(l[0], l[c], p) > 0) b = c; else a = c;
    }
    // Alow on edge --> return Det... <= 0
    return Det(l[a], l[b], p) < 0;
}
bool intersect_1pt(Point a, Point b,
    Point c, Point d, Point &r) {
    double D =  (b - a) % (d - c);
    if (cmp(D, 0) == 0) return false;
    double t =  ((c - a) % (d - c)) / D;
    double s = -((a - c) % (b - a)) / D;
    r = a + (b - a) * t;
    return cmp(t, 0) >= 0 && cmp(t, 1) <= 0 && cmp(s, 0) >= 0 && cmp(s, 1) <= 0;
}
Polygon convex_intersect(Polygon P, Polygon Q) {
    const int n = P.size(), m = Q.size();
    int a = 0, b = 0, aa = 0, ba = 0;
    enum { Pin, Qin, Unknown } in = Unknown;
    Polygon R;
    do {
        int a1 = (a+n-1) % n, b1 = (b+m-1) % m;
        double C = (P[a] - P[a1]) % (Q[b] - Q[b1]);
        double A = (P[a1] - Q[b]) % (P[a] - Q[b]);
        double B = (Q[b1] - P[a]) % (Q[b] - P[a]);
        Point r;
        if (intersect_1pt(P[a1], P[a], Q[b1], Q[b], r)) {
            if (in == Unknown) aa = ba = 0;
            R.push_back( r );
            in = B > 0 ? Pin : A > 0 ? Qin : in;
        }
        if (C == 0 && B == 0 && A == 0) {
            if (in == Pin) { b = (b + 1) % m; ++ba; }
            else            { a = (a + 1) % m; ++aa; }
        } else if (C >= 0) {
            if (A > 0) { if (in == Pin) R.push_back(P[a]); a = (a+1)%n; ++aa; }
            else       { if (in == Qin) R.push_back(Q[b]); b = (b+1)%m; ++ba; }
        } else {
            if (B > 0) { if (in == Qin) R.push_back(Q[b]); b = (b+1)%m; ++ba; }
            else       { if (in == Pin) R.push_back(P[a]); a = (a+1)%n; ++aa; }
        }
    } while ( (aa < n || ba < m) && aa < 2*n && ba < 2*m );
    if (in == Unknown) {
        if (in_convex(Q, P[0])) return P;
        if (in_convex(P, Q[0])) return Q;
    }
    return R;
}
double signed_area(Polygon p) {
    double area = 0;
    for(int i = 0; i < p.size(); i++) {
        int j = (i+1) % p.size();
        area += p[i].x*p[j].y - p[j].x*p[i].y;
    }
    return area / 2.0;
}
double area(const Polygon &p) {
    return fabs(signed_area(p));
}

#undef int
int main() {
#define int long long
    ios :: sync_with_stdio(0); cin.tie(0);
    cout << (fixed) << setprecision(4);
    int ntest; cin >> ntest;
    while (ntest--) {
        int n1, n2;
        cin >> n1 >> n2;
        Polygon a1, a2;
        a1.resize(n1);
        a2.resize(n2);

        REP(i,n1) cin >> a1[i];
        REP(i,n2) cin >> a2[i];

        auto p = convex_intersect(a1, a2);
        cout << signed_area(p) << endl;
    }
}