Submission #1138342

#	Time	Username	Problem	Language	Result	Execution time	Memory
1138342		SmuggingSpun	Election Campaign (JOI15_election_campaign)	C++20	10 / 100	40 ms	18444 KiB

election_campaign

#include<bits/stdc++.h>
#define taskname "A"
using namespace std;
typedef long long ll;
template<class T>void maximize(T& a, T b){
	if(a < b){
		a = b;
	}
}
const int lim = 1e5 + 5;
vector<int>g[lim];
int n, m, time_dfs = 0, low[lim], parent[lim], h[lim];
void dfs(int s){
	low[s] = ++time_dfs;
	for(int& d : g[s]){
		if(d != parent[s]){
			h[d] = h[parent[d] = s] + 1;
			dfs(d);
		}
	}
}
namespace sub1{
	bitset<lim>current, state[15];
	int c[15];
	void solve(){
		for(int i = 0; i < m; i++){
			int u, v;
			cin >> u >> v >> c[i];
			state[i].reset();
			state[i].set(u);
			state[i].set(v);
			while(u != v){
				if(h[u] < h[v]){
					swap(u, v);
				}
				state[i].set(u = parent[u]);
			}
		}
		ll ans = 0;
		for(int mask = (1 << m) - 1; mask > 0; mask--){
			current.reset();
			ll sum = 0;
			bool can = true;
			for(int i = 0; i < m; i++){
				if(1 << i & mask){
					if((current & state[i]).any()){
						can = false;
						break;
					}
					current |= state[i];
					sum += c[i];
				}
			}
			if(can){
				maximize(ans, sum);
			}
		}
		cout << ans;
	}
}
namespace sub23{
	vector<pair<int, int>>segment[lim];
	ll dp[lim];
	void solve(){
		for(int i = 0; i < m; i++){
			int a, b, c;
			cin >> a >> b >> c;
			if(a > b){
				swap(a, b);
			}
			segment[b].emplace_back(a, c);
		}
		dp[0] = 0;
		for(int i = 1; i <= n; i++){
			dp[i] = dp[i - 1];
			for(auto& [j, c] : segment[i]){
				maximize(dp[i], dp[j - 1] + c);
			}
		}
		cout << dp[n];
	}
}
namespace sub5{
	const int lim = 1e3 + 5;
	int c[lim];
	ll dp[lim][lim], f[lim];
	vector<pair<vector<int>, int>>item[lim];
	void solve(){
		for(int i = 0; i < m; i++){
			int u, v;
			vector<int>vertex;
			cin >> u >> v >> c[i];
			vertex.emplace_back(u);
			vertex.emplace_back(v);
			while(u != v){
				if(h[u] < h[v]){
					swap(u, v);
				}
				vertex.emplace_back(u = parent[u]);
			}
			vertex.pop_back();
			for(int& j : vertex){
				j = low[j];
			}
			sort(vertex.begin(), vertex.end());
			item[vertex.back()].emplace_back(vertex, i);
		}
		memset(f, -1, sizeof(f));
		memset(dp, 0, sizeof(dp));
		for(int len = 0; len < n; len++){
			for(int r = len + 1; r <= n; r++){
				int l = r - len;
				dp[l][r] = max(dp[l][r - 1], dp[l + 1][r]);
				for(auto& [low_vector, id] : item[r]){
					if(low_vector[0] < l){
						break;
					}
					if(f[id] == -1){
						f[id] = 0;
						for(int i = 1; i < low_vector.size(); i++){
							f[id] += dp[low_vector[i - 1] + 1][low_vector[i] - 1];
						}
					}
					maximize(dp[l][r], f[id] + dp[l][low_vector[0] - 1] + c[id]);
				}
			}
		}
		cout << dp[1][n];
	}
}
namespace sub46{
	void solve(){
		
	}
}
int main(){
	ios_base::sync_with_stdio(0); cin.tie(0); cout.tie(0);
	if(fopen(taskname".inp", "r")){
		freopen(taskname".inp", "r", stdin);
	}
	cin >> n;
	for(int i = 1; i < n; i++){
		int u, v;
		cin >> u >> v;
		g[u].emplace_back(v);
		g[v].emplace_back(u);
	}
	dfs(parent[1] = h[1] = 1);
	cin >> m;
	if(m <= 15){
		sub5::solve();
	}
	else{
		bool is_sub23 = (g[1].size() == 1 && g[1][0] == 2);
		for(int i = 2; i < n; i++){
			if(g[i].size() != 2 || min(g[i][0], g[i][1]) != i - 1 || (g[i][0] ^ g[i][1] ^ (i - 1)) != i + 1){
				is_sub23 = false;
				break;
			}
		}
		if(is_sub23 && g[n].size() == 1 && g[n][0] == n - 1){
			sub23::solve();
		}
		else if(n <= 1000 && m <= 1000){
			sub5::solve();
		}
		else{
			sub46::solve();
		}
	}
}

Compilation message (stderr)

election_campaign.cpp: In function 'int main()':
election_campaign.cpp:139:24: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
  139 |                 freopen(taskname".inp", "r", stdin);
      |                 ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~

• Subtask 1: 0 / 10
• Subtask 2: 5 / 5
• Subtask 3: 5 / 5
• Subtask 4: 0 / 30
• Subtask 5: 0 / 10
• Subtask 6: 0 / 40