Submission #379757

#	Time	Username	Problem	Language	Result	Execution time	Memory
379757		cgiosy	Mergers (JOI19_mergers)	C++17	0 / 100	52 ms	7780 KiB

mergers

    #include <bits/stdc++.h>
    using namespace std;
     
    int main() {
    	ios::sync_with_stdio(0);cin.tie(0);
    	int N, M, ans=1, t=0;
    	cin>>N>>M;
    	vector<int> C(N), S(N), L(M, 0x3f3f3f3f), R(M);
    	vector<vector<int>> G(N);
    	for(int i=1; i<N; i++) {
    		int x, y;
    		cin>>x>>y; --x, --y;
    		G[x].push_back(y);
    		G[y].push_back(x);
    	}
     
    	function<void(int, int)> f1=[&](int i, int p) {
    		S[i]=++t;
    		for(int j:G[i]) if(j!=p) f1(j, i);
    	};
    	f1(0, 0);
     
    	for(int i=0; i<N; i++) {
    		cin>>C[i], --C[i];
    		L[C[i]]=min(L[C[i]], S[i]);
    		R[C[i]]=max(R[C[i]], S[i]);
    	}
     
    	t=0;
    	function<pair<int, int>(int, int)> f2=[&](int i, int p) {
    		int a=L[C[i]], b=R[C[i]];
    		++t;
    		for(int j:G[i]) if(j!=p) {
    			auto[c,d]=f2(j, i);
    			a=min(a, c);
    			b=max(b, d);
    		}
    		if(i && S[i]<=a && b<=t) ans++, a=-1;
    		return make_pair(a, b);
    	};
	for(int i=0; i<N; i++) if(G[i].size()<2) { f2(i, i); break; }
     
    	cout<<ans/2<<'\n';
    }

• Subtask 1: 0 / 10
• Subtask 2: 0 / 24
• Subtask 3: 0 / 14
• Subtask 4: 0 / 22
• Subtask 5: 0 / 30