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Submission #205361

# Submission time Handle Problem Language Result Execution time Memory
205361 2020-02-28T16:27:10 Z TadijaSebez Olympic Bus (JOI20_ho_t4) C++11
100 / 100
 396 ms 4856 KB 
#include <bits/stdc++.h>
using namespace std;
#define ll long long
#define pb push_back
const int N=205;
const int M=50050;
const int inf=2e9+7;
struct Edge{int u,v,c,d;};
Edge edges[M];
bool bridge[M];
struct Bridges{
	static const int NSZ=205;
	vector<pair<int,int>> E[NSZ];
	vector<int> ans;
	int n,disc[NSZ],low[NSZ],tid;
	void init(int _n){n=_n;tid=0;ans.clear();for(int i=1;i<=n;i++)E[i].clear(),disc[i]=low[i]=0;}
	void AddEdge(int u,int v,int e){E[u].pb({v,e});E[v].pb({u,e});}
	void DFS(int u,int p){
		disc[u]=low[u]=++tid;
		for(auto e:E[u])if(e.second!=p){
			int v=e.first;
			if(!disc[v]){
				DFS(v,e.second);
				if(low[v]>disc[u])ans.pb(e.second);
				low[u]=min(low[u],low[v]);
			}else low[u]=min(low[u],disc[v]);
		}
	}
}GPH;
void FindBridges(vector<pair<int,int>> go[],int st,int n){
	GPH.init(n);
	vector<bool> was(n+1,0);
	function<void(int)> CNS=[&](int u){
		was[u]=1;
		for(auto e:go[u]){
			GPH.AddEdge(u,e.first,e.second);
			if(!was[e.first])CNS(e.first);
		}
	};
	CNS(st);
	GPH.DFS(st,-1);
	//printf(":D\n");
	for(int i:GPH.ans)bridge[i]=1;
}
struct DijkstraPQ{
	static const int N=205;
	int a[N],idx[N],val[N],n;
	void init(int _n,int st,int inf){
		n=_n;
		for(int i=1;i<=n;i++)a[i]=i,val[i]=inf;
		swap(a[st],a[1]);
		for(int i=1;i<=n;i++)idx[a[i]]=i;
		val[st]=0;
	}
	int size(){return n;}
	void Change(int x,int f){
		val[x]=f;
		int p=idx[x];
		while(p>1 && f<val[a[p/2]])a[p]=a[p/2],idx[a[p]]=p,p/=2;
		a[p]=x;idx[x]=p;
	}
	int top(){return a[1];}
	void pop(){
		int now=1;
		a[1]=a[n];n--;
		idx[a[1]]=1;
		while(now*2<=n){
			int ch=now*2;
			if(ch+1<=n && val[a[ch+1]]<val[a[ch]])ch++;
			if(val[a[now]]<=val[a[ch]])break;
			swap(a[now],a[ch]);
			idx[a[now]]=now;
			idx[a[ch]]=ch;
			now=ch;
		}
	}
};
void Dijkstra(vector<pair<int,int>> E[],int n,int st,int dist[],vector<pair<int,int>> go[]){
	for(int i=1;i<=n;i++)dist[i]=inf,go[i].clear();
	DijkstraPQ pq;pq.init(n,st,inf);
	dist[st]=0;
	while(pq.size()){
		int u=pq.top();
		pq.pop();
		for(auto e:E[u]){
			int v=e.first,w=edges[e.second].c;
			if(dist[v]>dist[u]+w){
				dist[v]=dist[u]+w;
				go[v].clear();
				//pq.push({-dist[v],v});
				pq.Change(v,dist[v]);
			}
			if(dist[v]==dist[u]+w)go[v].pb({u,e.second});
		}
	}
}
vector<pair<int,int>> E[N],R[N],T[N],go[N];
void BuildRev(int j,int m,int n){
	for(int i=1;i<=n;i++)T[i].clear();
	for(int i=1;i<=m;i++){
		if(i!=j)T[edges[i].u].pb({edges[i].v,i});
		else T[edges[i].v].pb({edges[i].u,i});
	}
}
int dist[2][2][N],tmp[N];
int main(){
	int n,m;
	scanf("%i %i",&n,&m);
	for(int i=1;i<=m;i++){
		scanf("%i %i %i %i",&edges[i].u,&edges[i].v,&edges[i].c,&edges[i].d);
		E[edges[i].u].pb({edges[i].v,i});
		R[edges[i].v].pb({edges[i].u,i});
	}
	Dijkstra(E,n,1,dist[0][0],go);
	FindBridges(go,n,n);
	Dijkstra(R,n,n,dist[0][1],go);
	Dijkstra(E,n,n,dist[1][0],go);
	FindBridges(go,1,n);
	Dijkstra(R,n,1,dist[1][1],go);
	ll ans=(ll)dist[0][0][n]+dist[1][0][1];
	for(int i=1;i<=m;i++){
		if(bridge[i]){
			BuildRev(i,m,n);
			Dijkstra(T,n,1,tmp,go);
			ll now=tmp[n];
			if(now==inf)continue;
			//printf("%i ",tmp[n]);
			Dijkstra(T,n,n,tmp,go);
			now+=tmp[1];
			//printf("%i ",tmp[1]);
			now+=edges[i].d;
			ans=min(ans,now);
			//printf("%i %lld\n",i,now);
		}else{
			int u=edges[i].u,v=edges[i].v,c=edges[i].c,d=edges[i].d;
			ll d1=dist[0][0][n];
			if(dist[0][0][v]<dist[0][0][u])d1=min(d1,(ll)dist[0][0][v]+c+dist[0][1][u]);
			ll d2=dist[1][0][1];
			if(dist[1][0][v]<dist[1][0][u])d2=min(d2,(ll)dist[1][0][v]+c+dist[1][1][u]);
			ans=min(ans,d1+d2+d);
		}
	}
	if(ans<inf)printf("%lld\n",ans);
	else printf("-1\n");
	return 0;
}

Compilation message

ho_t4.cpp: In function 'int main()':
ho_t4.cpp:108:7: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
  scanf("%i %i",&n,&m);
  ~~~~~^~~~~~~~~~~~~~~
ho_t4.cpp:110:8: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
   scanf("%i %i %i %i",&edges[i].u,&edges[i].v,&edges[i].c,&edges[i].d);
   ~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

Subtask #1
5.0 / 5.0

# Verdict Execution time Memory Grader output
1 Correct 6 ms 504 KB Output is correct
2 Correct 5 ms 376 KB Output is correct
3 Correct 6 ms 376 KB Output is correct
4 Correct 7 ms 376 KB Output is correct
5 Correct 5 ms 376 KB Output is correct
6 Correct 5 ms 376 KB Output is correct
7 Correct 6 ms 376 KB Output is correct
8 Correct 5 ms 376 KB Output is correct
9 Correct 5 ms 376 KB Output is correct
10 Correct 22 ms 504 KB Output is correct
11 Correct 25 ms 504 KB Output is correct
12 Correct 25 ms 504 KB Output is correct
13 Correct 6 ms 504 KB Output is correct
14 Correct 6 ms 376 KB Output is correct
15 Correct 6 ms 376 KB Output is correct
16 Correct 6 ms 376 KB Output is correct

Subtask #2
11.0 / 11.0

# Verdict Execution time Memory Grader output
1 Correct 30 ms 2424 KB Output is correct
2 Correct 31 ms 2424 KB Output is correct
3 Correct 33 ms 2424 KB Output is correct
4 Correct 6 ms 504 KB Output is correct
5 Correct 6 ms 376 KB Output is correct
6 Correct 5 ms 376 KB Output is correct
7 Correct 5 ms 376 KB Output is correct
8 Correct 5 ms 376 KB Output is correct
9 Correct 33 ms 2424 KB Output is correct
10 Correct 33 ms 2424 KB Output is correct
11 Correct 33 ms 2424 KB Output is correct
12 Correct 33 ms 2424 KB Output is correct
13 Correct 33 ms 2424 KB Output is correct
14 Correct 33 ms 2552 KB Output is correct

Subtask #3
21.0 / 21.0

# Verdict Execution time Memory Grader output
1 Correct 6 ms 504 KB Output is correct
2 Correct 5 ms 380 KB Output is correct
3 Correct 30 ms 3192 KB Output is correct
4 Correct 5 ms 380 KB Output is correct
5 Correct 36 ms 4088 KB Output is correct
6 Correct 5 ms 376 KB Output is correct
7 Correct 5 ms 376 KB Output is correct
8 Correct 34 ms 3188 KB Output is correct
9 Correct 35 ms 3192 KB Output is correct
10 Correct 36 ms 4600 KB Output is correct
11 Correct 36 ms 4604 KB Output is correct
12 Correct 38 ms 4856 KB Output is correct
13 Correct 5 ms 376 KB Output is correct
14 Correct 5 ms 376 KB Output is correct
15 Correct 5 ms 376 KB Output is correct
16 Correct 5 ms 376 KB Output is correct
17 Correct 5 ms 376 KB Output is correct
18 Correct 5 ms 376 KB Output is correct
19 Correct 35 ms 4344 KB Output is correct
20 Correct 35 ms 4088 KB Output is correct
21 Correct 34 ms 4216 KB Output is correct
22 Correct 36 ms 4088 KB Output is correct

Subtask #4
63.0 / 63.0

# Verdict Execution time Memory Grader output
1 Correct 6 ms 504 KB Output is correct
2 Correct 5 ms 376 KB Output is correct
3 Correct 6 ms 376 KB Output is correct
4 Correct 7 ms 376 KB Output is correct
5 Correct 5 ms 376 KB Output is correct
6 Correct 5 ms 376 KB Output is correct
7 Correct 6 ms 376 KB Output is correct
8 Correct 5 ms 376 KB Output is correct
9 Correct 5 ms 376 KB Output is correct
10 Correct 22 ms 504 KB Output is correct
11 Correct 25 ms 504 KB Output is correct
12 Correct 25 ms 504 KB Output is correct
13 Correct 6 ms 504 KB Output is correct
14 Correct 6 ms 376 KB Output is correct
15 Correct 6 ms 376 KB Output is correct
16 Correct 6 ms 376 KB Output is correct
17 Correct 30 ms 2424 KB Output is correct
18 Correct 31 ms 2424 KB Output is correct
19 Correct 33 ms 2424 KB Output is correct
20 Correct 6 ms 504 KB Output is correct
21 Correct 6 ms 376 KB Output is correct
22 Correct 5 ms 376 KB Output is correct
23 Correct 5 ms 376 KB Output is correct
24 Correct 5 ms 376 KB Output is correct
25 Correct 33 ms 2424 KB Output is correct
26 Correct 33 ms 2424 KB Output is correct
27 Correct 33 ms 2424 KB Output is correct
28 Correct 33 ms 2424 KB Output is correct
29 Correct 33 ms 2424 KB Output is correct
30 Correct 33 ms 2552 KB Output is correct
31 Correct 6 ms 504 KB Output is correct
32 Correct 5 ms 380 KB Output is correct
33 Correct 30 ms 3192 KB Output is correct
34 Correct 5 ms 380 KB Output is correct
35 Correct 36 ms 4088 KB Output is correct
36 Correct 5 ms 376 KB Output is correct
37 Correct 5 ms 376 KB Output is correct
38 Correct 34 ms 3188 KB Output is correct
39 Correct 35 ms 3192 KB Output is correct
40 Correct 36 ms 4600 KB Output is correct
41 Correct 36 ms 4604 KB Output is correct
42 Correct 38 ms 4856 KB Output is correct
43 Correct 5 ms 376 KB Output is correct
44 Correct 5 ms 376 KB Output is correct
45 Correct 5 ms 376 KB Output is correct
46 Correct 5 ms 376 KB Output is correct
47 Correct 5 ms 376 KB Output is correct
48 Correct 5 ms 376 KB Output is correct
49 Correct 35 ms 4344 KB Output is correct
50 Correct 35 ms 4088 KB Output is correct
51 Correct 34 ms 4216 KB Output is correct
52 Correct 36 ms 4088 KB Output is correct
53 Correct 42 ms 2936 KB Output is correct
54 Correct 44 ms 3064 KB Output is correct
55 Correct 41 ms 2936 KB Output is correct
56 Correct 6 ms 376 KB Output is correct
57 Correct 6 ms 376 KB Output is correct
58 Correct 171 ms 2296 KB Output is correct
59 Correct 200 ms 2632 KB Output is correct
60 Correct 262 ms 2300 KB Output is correct
61 Correct 170 ms 2296 KB Output is correct
62 Correct 196 ms 2552 KB Output is correct
63 Correct 256 ms 2424 KB Output is correct
64 Correct 281 ms 2424 KB Output is correct
65 Correct 304 ms 2552 KB Output is correct
66 Correct 396 ms 2424 KB Output is correct
67 Correct 26 ms 2408 KB Output is correct
68 Correct 35 ms 2424 KB Output is correct
69 Correct 33 ms 2428 KB Output is correct
70 Correct 43 ms 2936 KB Output is correct
71 Correct 41 ms 2936 KB Output is correct
72 Correct 38 ms 2936 KB Output is correct
73 Correct 40 ms 3068 KB Output is correct
74 Correct 42 ms 2936 KB Output is correct