public void Empty()
{
var ts1 = new TwoSat(0);
ts1.Satisfiable().Should().BeTrue();
ts1.Answer().Should().Equal(Array.Empty <bool>());
}
public void StressOK()
{
var mt = MTRandom.Create();
for (int phase = 0; phase < 10000; phase++)
{
int n = mt.Next(1, 21);
int m = mt.Next(1, 101);
var expect = new bool[n];
for (int i = 0; i < n; i++)
{
expect[i] = mt.NextBool();
}
var ts = new TwoSat(n);
var xs = new int[m];
var ys = new int[m];
var types = new int[m];
for (int i = 0; i < m; i++)
{
int x = mt.Next(0, n);
int y = mt.Next(0, n);
int type = mt.Next(0, 3);
xs[i] = x;
ys[i] = y;
types[i] = type;
if (type == 0)
{
ts.AddClause(x, expect[x], y, expect[y]);
}
else if (type == 1)
{
ts.AddClause(x, !expect[x], y, expect[y]);
}
else
{
ts.AddClause(x, expect[x], y, !expect[y]);
}
}
ts.Satisfiable().Should().BeTrue();
var actual = ts.Answer();
for (int i = 0; i < m; i++)
{
int x = xs[i], y = ys[i], type = types[i];
if (type == 0)
{
(actual[x] == expect[x] || actual[y] == expect[y]).Should().BeTrue();
}
else if (type == 1)
{
(actual[x] != expect[x] || actual[y] == expect[y]).Should().BeTrue();
}
else
{
(actual[x] == expect[x] || actual[y] != expect[y]).Should().BeTrue();
}
}
}
}
public void One()
{
{
var ts = new TwoSat(1);
ts.AddClause(0, true, 0, true);
ts.AddClause(0, false, 0, false);
ts.Satisfiable().Should().BeFalse();
}
{
var ts = new TwoSat(1);
ts.AddClause(0, true, 0, true);
ts.Satisfiable().Should().BeTrue();
ts.Answer().Should().Equal(true);
}
{
var ts = new TwoSat(1);
ts.AddClause(0, false, 0, false);
ts.Satisfiable().Should().BeTrue();
ts.Answer().Should().Equal(false);
}
}