Submission #876405

#	Time	Username	Problem	Language	Result	Execution time	Memory
876405		cpptowin	Commuter Pass (JOI18_commuter_pass)	C++14	100 / 100	231 ms	94860 KiB

commuter_pass

#include<bits/stdc++.h>
#define fo(i,d,c) for(int i=d;i<=c;i++)
#define fod(i,c,d) for(int i=c;i>=d;i--)
#define maxn 1000010
#define N 1010
#define fi first
#define se second
#define pb emplace_back
#define en cout<<"\n";
#define int long long
#define inf (int)2e18
#define pii pair<int,int>
#define vii vector<pii>
#define lb(x) x&-x
#define bit(i,j) ((i>>j)&1)
#define offbit(i,j) (i^(1<<j))
#define onbit(i,j) (i|(1<<j))
#define vi vector<int>
template <typename T1, typename T2> bool minimize(T1 &a, T2 b){if (a > b) {a = b; return true;} return false;}
template <typename T1, typename T2> bool maximize(T1 &a, T2 b){if (a < b) {a = b; return true;} return false;}
using namespace std;
int n,m;
vii ke[maxn];
void dijkstra1(int inp,int d[])
{
    priority_queue<pii,vii,greater<pii>> q;
    fo(i,1,n) d[i] = inf;
    d[inp] = 0;
    q.push({0,inp});
    while(q.size())
    {
        auto [du,u] = q.top();
        q.pop();
        if(du != d[u]) continue;
        for(auto [v,w] : ke[u])
        {
            if(d[v] > d[u] + w)
            {
                d[v] = d[u] + w;
                q.push({d[v],v});
            }
        }
    }
}
int du[maxn],dv[maxn],ds[maxn],dt[maxn];
int dpu[maxn],dpv[maxn];
vi adj[maxn];
array<int,3> edge[maxn];
int ans;
int vis[maxn];
void dfs(int u)
{
    vis[u] = 1;
    for(int v : adj[u])
    {
        if(!vis[v]) dfs(v);
        dpu[u] = min(dpu[u],min(dpu[v],du[v]));
        dpv[u] = min(dpv[u],min(dpv[v],dv[v]));
    }
    ans = min({ans,dpu[u] + dv[u],dpv[u] + du[u]});
}
int s,t,u,v;
main()
{
    #define name "TASK"
    if(fopen(name".inp","r"))
    {
       freopen(name".inp","r",stdin);
       freopen(name".out","w",stdout);
    }
    ios_base::sync_with_stdio(false);cin.tie(NULL);
    cin >> n >> m;
    cin >> s >> t >> u >> v;
    fo(i,1,m)
    {
        cin >> edge[i][0] >> edge[i][1] >> edge[i][2];
        ke[edge[i][0]].pb(edge[i][1],edge[i][2]);
        ke[edge[i][1]].pb(edge[i][0],edge[i][2]);
    }
    dijkstra1(u,du);
    dijkstra1(v,dv);
    dijkstra1(s,ds);
    dijkstra1(t,dt);
    fo(i,1,m)
    {
        if(ds[edge[i][0]] + edge[i][2] + dt[edge[i][1]] == ds[t]) adj[edge[i][0]].pb(edge[i][1]);
        if(ds[edge[i][1]] + edge[i][2] + dt[edge[i][0]] == ds[t]) adj[edge[i][1]].pb(edge[i][0]);
    }
    fo(i,1,n) dpu[i] = dpv[i] = 2e18;
    ans = du[v];
    dfs(s);
    cout << ans;
}

Compilation message (stderr)

commuter_pass.cpp: In function 'void dijkstra1(long long int, long long int*)':
commuter_pass.cpp:32:14: warning: structured bindings only available with '-std=c++17' or '-std=gnu++17'
   32 |         auto [du,u] = q.top();
      |              ^
commuter_pass.cpp:35:18: warning: structured bindings only available with '-std=c++17' or '-std=gnu++17'
   35 |         for(auto [v,w] : ke[u])
      |                  ^
commuter_pass.cpp: At global scope:
commuter_pass.cpp:63:1: warning: ISO C++ forbids declaration of 'main' with no type [-Wreturn-type]
   63 | main()
      | ^~~~
commuter_pass.cpp: In function 'int main()':
commuter_pass.cpp:68:15: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   68 |        freopen(name".inp","r",stdin);
      |        ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~
commuter_pass.cpp:69:15: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   69 |        freopen(name".out","w",stdout);
      |        ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~

• Subtask 1: 16 / 16
• Subtask 2: 15 / 15
• Subtask 3: 24 / 24
• Subtask 4: 45 / 45