基环树DP，攻的当受的儿子，f表选，g表不选。并查集维护攻受关系。若有环则记录，DP受的后把它当祖宗，再DP攻的。 #include <cstdio> #include <iostream> #include <cstring> #include <...
// luogu-judger-enable-o2 #include <cstdio> //#include <iostream> #include <cstring> #include <algorithm> #include <cmath> #define R(a,b,c) for(register int a = (b); (...
