Submission #339707

#	Time	Username	Problem	Language	Result	Execution time	Memory
339707		couplefire	Olympic Bus (JOI20_ho_t4)	C++17	100 / 100	171 ms	4204 KiB

ho_t4

#include<bits/stdc++.h>
using namespace std;
#define int long long
const int inf=0x0f0f0f0f0f0f0f0f;
int n,m,g[210][210],h[210][210],f[210][210];
bool vis[210];
void Dijkstra(int S,int *dis,int *fa){
	for(int i=0;i<=n;i++)dis[i]=inf,vis[i]=false;
	dis[S]=0;
	while(true){
		int x=0;
		for(int i=1;i<=n;i++)if(!vis[i]&&dis[i]<dis[x])x=i;
		if(!x)break;
		vis[x]=true;
		for(int y=1;y<=n;y++)if(dis[y]>dis[x]+g[x][y])dis[y]=dis[x]+g[x][y],fa[y]=x;
	}
//	for(int i=1;i<=n;i++)printf("%d ",dis[i]);puts("");
}
int dis1[210],fa1[210],sid1[210],af1[210],disn[210],fan[210],sidn[210],afn[210],dist[210],fat[210];
int u[51000],v[51000],c[51000],d[51000];
int res=inf;
signed main(){
	scanf("%lld%lld",&n,&m),memset(g,inf,sizeof(g)),memset(f,inf,sizeof(f));
	for(int i=1;i<=m;i++){
		scanf("%lld%lld%lld%lld",&u[i],&v[i],&c[i],&d[i]);
		if(g[u[i]][v[i]]>=c[i])f[u[i]][v[i]]=g[u[i]][v[i]],g[u[i]][v[i]]=c[i];
		else f[u[i]][v[i]]=min(f[u[i]][v[i]],c[i]);
	}
//	for(int i=1;i<=n;i++){for(int j=1;j<=n;j++)printf("%d ",g[i][j]);puts("");}
//	for(int i=1;i<=n;i++){for(int j=1;j<=n;j++)printf("%d ",f[i][j]);puts("");}
	Dijkstra(1,dis1,fa1),Dijkstra(n,disn,fan);
	res=min(res,dis1[n]+disn[1]);
	for(int i=1;i<=n;i++)for(int j=1;j<=n;j++)h[i][j]=g[i][j];
	for(int i=1;i<=n;i++)for(int j=1;j<=n;j++)g[i][j]=h[j][i];
	Dijkstra(1,sid1,af1),Dijkstra(n,sidn,afn);
	for(int i=1;i<=n;i++)for(int j=1;j<=n;j++)g[i][j]=h[i][j];
	memcpy(h,g,sizeof(g));
	for(int i=1;i<=m;i++){
		int tmpa=g[u[i]][v[i]],tmpb=g[v[i]][u[i]];
		g[u[i]][v[i]]=f[u[i]][v[i]];
		g[v[i]][u[i]]=min(g[v[i]][u[i]],c[i]);
		
		int p=0;
		if(fa1[v[i]]!=u[i]||dis1[u[i]]+c[i]!=dis1[v[i]])p=min(dis1[n],dis1[v[i]]+c[i]+sidn[u[i]]);
		else Dijkstra(1,dist,fat),p=dist[n];
		int q=0;
		if(fan[v[i]]!=u[i]||disn[u[i]]+c[i]!=disn[v[i]])q=min(disn[1],disn[v[i]]+c[i]+sid1[u[i]]);
		else Dijkstra(n,dist,fat),q=dist[1];
		
		g[u[i]][v[i]]=tmpa;
		g[v[i]][u[i]]=tmpb;
		res=min(res,p+q+d[i]);
	}
	printf("%lld\n",res==inf?-1:res);
	return 0;
}

Compilation message (stderr)

ho_t4.cpp: In function 'int main()':
ho_t4.cpp:23:35: warning: overflow in conversion from 'long long int' to 'int' changes value from '1085102592571150095' to '252645135' [-Woverflow]
   23 |  scanf("%lld%lld",&n,&m),memset(g,inf,sizeof(g)),memset(f,inf,sizeof(f));
      |                                   ^~~
ho_t4.cpp:23:59: warning: overflow in conversion from 'long long int' to 'int' changes value from '1085102592571150095' to '252645135' [-Woverflow]
   23 |  scanf("%lld%lld",&n,&m),memset(g,inf,sizeof(g)),memset(f,inf,sizeof(f));
      |                                                           ^~~
ho_t4.cpp:23:7: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
   23 |  scanf("%lld%lld",&n,&m),memset(g,inf,sizeof(g)),memset(f,inf,sizeof(f));
      |  ~~~~~^~~~~~~~~~~~~~~~~~
ho_t4.cpp:25:8: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
   25 |   scanf("%lld%lld%lld%lld",&u[i],&v[i],&c[i],&d[i]);
      |   ~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

• Subtask 1: 5 / 5
• Subtask 2: 11 / 11
• Subtask 3: 21 / 21
• Subtask 4: 63 / 63