Submission #923016

#	Time	Username	Problem	Language	Result	Execution time	Memory
923016		vjudge1	Olympic Bus (JOI20_ho_t4)	C++17	100 / 100	365 ms	7900 KiB

ho_t4

#include <bits/stdc++.h>

#pragma GCC optimize("Ofast")
#pragma GCC target("avx2")

using namespace std;

#define ll long long
#define ld long double
#define pb push_back
#define pf push_front
#define pii pair<int,int>
#define all(v) v.begin(),v.end()
#define F first
#define S second
#define mem(a,i) memset(a,i,sizeof(a))
#define sz(s) (int)s.size()
#define int ll
#define y1 yy
#define maksim gay
#define ppb pop_back
#define gcd(a,b) __gcd(a,b)
#define in insert

const int dx[4]={-1,0,1,0};
const int dy[4]={0,-1,0,1};

const int inf=1e16;
const int N=5e4+100;
const int MAX=210;
const int mod=1e9+7;


int n,m;
int a[N],b[N],c[N],dv[N];
vector<pii> g[MAX];
vector<pii> g1[MAX];
int use[MAX];
int cmp[MAX];
vector<int> top;

void dfs(int v){
  use[v]=1;
  for(auto to:g[v]){
    if(!use[to.F])dfs(to.F);
  }
  top.pb(v);
}

void dfs1(int v,int c){
  cmp[v]=c;
  for(auto to:g1[v]){
    if(!cmp[to.F]){
      dfs1(to.F,c);
    }
  }
}

int dp[MAX][MAX];

int ban[N];
int d[MAX];

int solve(int x){
  int ans=0;
  vector<pii> g[MAX];
  for(int i=1;i<=m;i++){
    if(i==x){
      g[b[i]].pb({a[i],c[i]});
    }
    else{
      g[a[i]].pb({b[i],c[i]});
    }
  }
  {
    for(int i=1;i<=n;i++)d[i]=inf;
    d[1]=0;
    mem(use,0);
    for(int i=1;i<=n;i++){
      int v=-1;
      for(int j=1;j<=n;j++){
        if(!use[j]&&(v==-1||d[j]<d[v])){
          v=j;
        }
      }
      use[v]=1;
      for(auto to:g[v]){
        if(d[to.F]>d[v]+to.S){
          d[to.F]=d[v]+to.S;
        }
      }
    }
    ans+=d[n];
  }
  {
    for(int i=1;i<=n;i++)d[i]=inf;
    d[n]=0;
    mem(use,0);
    for(int i=1;i<=n;i++){
      int v=-1;
      for(int j=1;j<=n;j++){
        if(!use[j]&&(v==-1||d[j]<d[v])){
          v=j;
        }
      }
      use[v]=1;
      for(auto to:g[v]){
        if(d[to.F]>d[v]+to.S){
          d[to.F]=d[v]+to.S;
        }
      }
    }
    ans+=d[1];
  }
  // cout<<x<<" "<<ans<<"\n";
  return ans;
}

vector<int> reb;
vector<int> fff;

void dfs2(int v,int en){
  use[v]=1;
  if(v==en){
    // cout<<sz(fff)<<"\n";
    for(int x:fff)reb.pb(x);
    return;
  }
  for(auto to:g1[v]){
    if(use[to.F]||dp[en][to.F]+c[to.S]!=dp[en][v])continue;
    fff.pb(to.S);
    dfs2(to.F,en);
    fff.ppb();
  }
}

void SUB1(){
  mem(use,0);
  dfs2(1,n);
  mem(use,0);
  dfs2(n,1);
  int ans=min(inf,dp[1][n]+dp[n][1]);
  for(int x:reb){
    ans=min(ans,solve(x)+dv[x]);
    ban[x]=1;
  }
  // cout<<sz(reb)<<"\n";
  for(int i=1;i<=m;i++){
    if(!ban[i]){
      int c1n=dp[1][n];
      {
        c1n=min(c1n,dp[1][b[i]]+c[i]+dp[a[i]][n]);
        // cout<<1<<" "<<b[i]<<" "<<a[i]<<" "<<n<<"\n";
      }
      int cn1=dp[n][1];
      {
        cn1=min(cn1,dp[n][b[i]]+c[i]+dp[a[i]][1]);
        // cout<<n<<" "<<b[i]<<" "<<a[i]<<" "<<1<<"\n";
      }
      // cout<<i<<" "<<c1n<<" "<<cn1<<"\n";
      ans=min(ans,c1n+cn1+dv[i]);
    }
  }
  if(ans!=inf)cout<<ans<<"\n";
  else cout<<-1<<"\n";
}

void solve(){
  cin>>n>>m;
  for(int i=1;i<=m;i++){
    cin>>a[i]>>b[i]>>c[i]>>dv[i];
    g[a[i]].pb({b[i],c[i]});
    g1[b[i]].pb({a[i],i});
  }
  for(int i=1;i<=n;i++){
    if(!use[i]){
      dfs(i);
    }
  }
  int cnt=0;
  reverse(all(top));
  for(int x:top){
    if(!cmp[x]){
      dfs1(x,++cnt);
    }
  }
  for(int i=1;i<=n;i++){
    for(int j=1;j<=n;j++){
      if(i!=j)dp[i][j]=inf;
    }
  }
  for(int i=1;i<=m;i++){
    dp[a[i]][b[i]]=min(dp[a[i]][b[i]],c[i]);
  }
  for(int k=1;k<=n;k++){
    for(int i=1;i<=n;i++){
      for(int j=1;j<=n;j++){
        dp[i][j]=min(dp[i][j],dp[i][k]+dp[k][j]);
      }
    }
  }
  // cout<<-1<<"\n";
  // return;
  SUB1();
}

main(){
  // freopen("prizes.in", "r", stdin);
  // freopen("prizes.out", "w", stdout);
  ios_base::sync_with_stdio(0);
  cin.tie(0);
  cout.tie(0);
  int t=1;
  // cin>>t;
  while(t--){
    solve();
  }
}

Compilation message (stderr)

ho_t4.cpp:207:1: warning: ISO C++ forbids declaration of 'main' with no type [-Wreturn-type]
  207 | main(){
      | ^~~~

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