int getChild(Mate* mate, int level, int take) const {
assert(1 <= level && level <= n);
int i = n - level;
Graph::EdgeInfo const& e = graph.edgeInfo(i);
assert(e.v1 <= e.v2);
if (take) {
switch (takable(mate, e)) {
case NO:
return 0;
case HIT:
return -1;
case YES:
break;
}
int w1 = mate[e.v1 - e.v0];
int w2 = mate[e.v2 - e.v0];
if (w1 > 0) mate[w1 - e.v0] = w2;
if (w2 > 0) mate[w2 - e.v0] = w1;
if (e.v1final || w1 != e.v1) mate[e.v1 - e.v0] = 0;
if (e.v2final || w2 != e.v2) mate[e.v2 - e.v0] = 0;
}
else {
if (!leavable(mate, e)) return 0;
Mate& w1 = mate[e.v1 - e.v0];
Mate& w2 = mate[e.v2 - e.v0];
if (e.v1final || (e.v1final2 && w1 == e.v1)) w1 = 0;
if (e.v2final || (e.v2final2 && w2 == e.v2)) w2 = 0;
}
if (++i == n) return 0;
shiftMate(mate, e.v0, graph.edgeInfo(i).v0);
while (lookahead) {
Graph::EdgeInfo const& e = graph.edgeInfo(i);
assert(e.v1 <= e.v2);
if (takable(mate, e) != NO) break;
if (!leavable(mate, e)) return 0;
if (++i == n) return 0;
Mate& w1 = mate[e.v1 - e.v0];
Mate& w2 = mate[e.v2 - e.v0];
if (e.v1final || (e.v1final2 && w1 == e.v1)) w1 = 0;
if (e.v2final || (e.v2final2 && w2 == e.v2)) w2 = 0;
shiftMate(mate, e.v0, graph.edgeInfo(i).v0);
}
assert(i < n);
return n - i;
}
int getChild(Mate* mate, int level, bool take) const {
assert(1 <= level && level <= n);
int i = n - level;
Graph::EdgeInfo const& e = graph.edgeInfo(i);
Mate& w1 = mate[e.v1 - e.v0];
Mate& w2 = mate[e.v2 - e.v0];
IntSubset const* c1 = constraints[e.v1];
IntSubset const* c2 = constraints[e.v2];
assert(e.v1 <= e.v2);
// std::cerr << "\ne" << i << (take ? ": T " : ": F ")
// << graph.vertexName(e.v1) << "-" << graph.vertexName(e.v2)
// << " ";
// print(std::cerr, mate);
if (take) {
if (!takable(c1, w1, e.v1final)) return 0;
if (!takable(c2, w2, e.v2final)) return 0;
if (c1) ++w1;
if (c2) ++w2;
}
else {
if (!leavable(c1, w1, e.v1final)) return 0;
if (!leavable(c2, w2, e.v2final)) return 0;
}
if (e.v1final) w1 = 0;
if (e.v2final) w2 = 0;
if (++i == n) return -1;
shiftMate(mate, graph.edgeInfo(i).v0 - e.v0);
while (true) {
Graph::EdgeInfo const& e = graph.edgeInfo(i);
Mate& w1 = mate[e.v1 - e.v0];
Mate& w2 = mate[e.v2 - e.v0];
IntSubset const* c1 = constraints[e.v1];
IntSubset const* c2 = constraints[e.v2];
assert(e.v1 <= e.v2);
if (takable(c1, w1, e.v1final) && takable(c2, w2, e.v2final)) break;
if (!leavable(c1, w1, e.v1final)) return 0;
if (!leavable(c2, w2, e.v2final)) return 0;
if (e.v1final) w1 = 0;
if (e.v2final) w2 = 0;
if (++i == n) return -1;
shiftMate(mate, graph.edgeInfo(i).v0 - e.v0);
}
assert(i < n);
return n - i;
}