Submission #974043

#	Time	Username	Problem	Language	Result	Execution time	Memory
974043		happy_node	Reconstruction Project (JOI22_reconstruction)	C++17	3 / 100	5005 ms	1048576 KiB

reconstruction

#include <bits/stdc++.h>
using namespace std;

typedef long long ll;
const int MX=505;

int N,M,Q;

struct DSU {
	int par[MX], sz[MX];

	int fd(int v) {
		return par[v]==v?v:par[v]=fd(par[v]);
	}

	bool merge(int u, int v) {
		u=fd(u),v=fd(v);
		if(u==v) return false;
		if(sz[u]>sz[v]) swap(u,v);
		par[u]=v;
		sz[v]+=sz[u];
		return true;
	}

	void reset() {
		for(int i=1;i<=N;i++) par[i]=i,sz[i]=1;
	}
} ds;

set<pair<int,int>> adj[MX];

set<array<int,3>> E;

array<int,3> bfs(int S, int T) {
	queue<int> q;
	q.push(S);
	
	vector<array<int,3>> dist(N+1,{-1,-1,-1});
	dist[S]={(int)1e9,0,0};

	while(!q.empty()) {
		auto v=q.front(); q.pop();
		for(auto [u,w]:adj[v]) {
			if(dist[u][0]!=-1) continue;

			array<int,3> cur={w,u,v};
			dist[u]=min(cur,dist[v]);
			q.push(u);
		}
	}

	return dist[T];
}

array<int,3> BFS(int S, int T) {
	queue<int> q;
	q.push(S);
	
	vector<array<int,3>> dist(N+1,{-1,-1,-1});
	dist[S]={0,0,0};

	while(!q.empty()) {
		auto v=q.front(); q.pop();
		for(auto [u,w]:adj[v]) {
			if(dist[u][0]!=-1) continue;

			array<int,3> cur={w,u,v};
			dist[u]=max(cur,dist[v]);
			q.push(u);
		}
	}

	return dist[T];
}

vector<array<int,3>> PF[100000+5], SF[100000+5];

int main() {
	cin.tie(0); ios_base::sync_with_stdio(0);

	cin>>N>>M;

	vector<array<int,3>> edges;

	for(int i=0;i<M;i++) {
		int u,v,w;
		cin>>u>>v>>w;
		edges.push_back({w,u,v});
	}		

	sort(edges.begin(),edges.end());

	int i=0;
	for(auto [w,u,v]:edges) {
		auto [ww,uu,vv]=bfs(u,v);
		if(ww!=-1) {
			adj[uu].erase({vv,ww});
			adj[vv].erase({uu,ww});
			E.erase({ww,min(uu,vv),max(uu,vv)});
		}
		adj[u].insert({v,w});
		adj[v].insert({u,w});
		E.insert({w,min(u,v),max(u,v)});
		for(auto [ww,uu,vv]:E) {
			PF[i].push_back({ww,uu,vv});
		}
		reverse(PF[i].begin(),PF[i].end());
		i++;
	}

	reverse(edges.begin(),edges.end());
	E.clear();
	for(int i=1;i<=N;i++) adj[i].clear();

	i=M-1;
	for(auto [w,u,v]:edges) {
		auto [ww,uu,vv]=BFS(u,v);
		if(ww!=-1) {
			adj[uu].erase({vv,ww});
			adj[vv].erase({uu,ww});
			E.erase({ww,min(uu,vv),max(uu,vv)});
		}
		adj[u].insert({v,w});
		adj[v].insert({u,w});
		E.insert({w,min(u,v),max(u,v)});
		for(auto [ww,uu,vv]:E) {
			SF[i].push_back({ww,uu,vv});
		}
		i--;
	}

	reverse(edges.begin(),edges.end());

	cin>>Q;

	int p=-1;
	for(int i=0;i<Q;i++) {
		int x;
		cin>>x;
		
		while(p+1<edges.size() && x>=edges[p+1][0]) {
			p++;
		}

		ds.reset();
		ll res=0;
		if(p==(int)edges.size()-1) {
			// PF back()
			for(auto [w,u,v]:PF[p]) {
				res+=x-w;
			}
		} else if(p==-1) {
			// SF[0]
			for(auto [w,u,v]:SF[0]) {
				res+=w-x;
			}
		} else {
			// PF[p], Sf[p+1]
			int i=0,j=0; // 2 pointers
			while(i<PF[p].size()&&j<SF[p+1].size()) {
				auto [w,u,v]=PF[p][i];
				auto [ww,uu,vv]=SF[p+1][j];

				if(x-w<ww-x) {
					if(ds.merge(u,v))
						res+=x-w;
					i++;
				} else {
					if(ds.merge(uu,vv))
						res+=ww-x;
					j++;
				}
			}
			while(i<PF[p].size()) {
				auto [w,u,v]=PF[p][i];
				if(ds.merge(u,v))
					res+=x-w;
				i++;
			}

			while(j<SF[p+1].size()) {
				auto [w,u,v]=SF[p+1][j];
				if(ds.merge(u,v))
					res+=w-x;
				j++;
			}
		}

		cout<<res<<'\n';
	}
}

Compilation message (stderr)

reconstruction.cpp: In function 'int main()':
reconstruction.cpp:141:12: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<std::array<int, 3> >::size_type' {aka 'long unsigned int'} [-Wsign-compare]
  141 |   while(p+1<edges.size() && x>=edges[p+1][0]) {
      |         ~~~^~~~~~~~~~~~~
reconstruction.cpp:160:11: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<std::array<int, 3> >::size_type' {aka 'long unsigned int'} [-Wsign-compare]
  160 |    while(i<PF[p].size()&&j<SF[p+1].size()) {
      |          ~^~~~~~~~~~~~~
reconstruction.cpp:160:27: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<std::array<int, 3> >::size_type' {aka 'long unsigned int'} [-Wsign-compare]
  160 |    while(i<PF[p].size()&&j<SF[p+1].size()) {
      |                          ~^~~~~~~~~~~~~~~
reconstruction.cpp:174:11: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<std::array<int, 3> >::size_type' {aka 'long unsigned int'} [-Wsign-compare]
  174 |    while(i<PF[p].size()) {
      |          ~^~~~~~~~~~~~~
reconstruction.cpp:181:11: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<std::array<int, 3> >::size_type' {aka 'long unsigned int'} [-Wsign-compare]
  181 |    while(j<SF[p+1].size()) {
      |          ~^~~~~~~~~~~~~~~

• Subtask 1: 3 / 3
• Subtask 2: 0 / 4
• Subtask 3: 0 / 7
• Subtask 4: 0 / 28
• Subtask 5: 0 / 35
• Subtask 6: 0 / 23