我正在编写一个蛮力算法来解决这样的顶点覆盖:
BruteForceVertexCover( Graph G = (V,E) ){
for size= 1 ... |V|
vector<int> v = {0...size-1}
do{
if(test(G, v)) return v; //test if v covers G
}
while(v has next combinations of lenght size);
return empty vector<int>;
}
//this stops when find a answer, and it will find,
//since it tries all combinations of all sizes
在哪里
bool test( Graph G = (V,E), vector<int> v ){
for each u in v:
for each w in G[u]
remove u from G[w] //this is linear in size of vector G[w]
clear G[v] //removed all (bidirectional) edges that have u
for i = 0 ... |V|
if(G[i] is not empty) return false;
return true;
}
我在很多图上尝试这个(但它们的最大尺寸是 20 个顶点),这需要十年的时间......我可以对这个蛮力做任何优化,让它运行得更快吗?