Submission #807474

#	Time	Username	Problem	Language	Result	Execution time	Memory
807474		amine_aroua	Commuter Pass (JOI18_commuter_pass)	C++17	100 / 100	437 ms	23644 KiB

commuter_pass

#include <bits/stdc++.h>
//#pragma GCC optimize("O3")
//#pragma GCC optimize("unroll-loops")
using namespace std;
#define int long long
#define vi vector<int>
#define vl vector<long long>
#define vii vector<pair<int,int>>
#define vll vector<pair<long long,long long>>
#define pb push_back
#define ll long long
#define ld long double
#define nl '\n'
#define boost ios::sync_with_stdio(false)
#define mp make_pair
#define se second
#define fi first
#define fore(i, y) for(int i = 0; i < y; i++)
#define forr(i,x,y) for(int i = x;i<=y;i++)
#define forn(i,y,x) for(int i = y; i >= x; i--)
#define all(v) v.begin(),v.end()
#define sz(v) v.size()
#define clr(v,k) memset(v,k,sizeof(v))
#define rall(v) v.rbegin() , v.rend()
#define pii pair<int,int>
#define pll pair<ll , ll>

const ll MOD = 1e9 + 7;
const int INF = 1e18 + 1;
const int inf = 1e9 + 1;

ll gcd(ll a , ll b) {return b ? gcd(b , a % b) : a ;} // greatest common divisor (gcd)
ll lcm(ll a , ll b) {return a * (b / gcd(a , b));} // least common multiple (lcm)

// HERE IS THE SOLUTION
const int N = 100000;
vii adj[N];
vi dp(N , INF) , dp0(N , INF);
int n , m , s , t , u , v;
vi spS , spT , spV , spU;
int dfs(int x)
{
    int &ans = dp[x];
    if(ans != INF)
        return ans;
    ans = spV[x];
    for(auto [y,c] : adj[x])
    {
        if(spS[x] + spT[y] + c== spS[t])
            ans = min(ans , dfs(y));
    }
    return ans;
}
int dfs0(int x)
{
    int &ans = dp0[x];
    if(ans != INF)
        return ans;
    ans = spV[x];
    for(auto [y,c] : adj[x])
    {
        if(spS[y] + spT[x] + c== spS[t])
            ans = min(ans , dfs0(y));
    }
    return ans;
}
vi  dijkstra(int start)
{
    vi dist(n , INF);
    priority_queue<pii> pq;
    pq.push({0 , start});
    dist[start] = 0;
    vector<bool> vis(n , 0);
    while(!pq.empty())
    {
        int cur = pq.top().se;
        pq.pop();
        if(vis[cur])
            continue;
        vis[cur] = 1;
        for(auto [x , c] : adj[cur])
        {
            if(dist[x] > dist[cur] + c){
                dist[x] = dist[cur] + c;
                pq.push({-dist[x] , x});
            }
        }
    }
    return dist;
}
bool cmp(int &a , int &b)
{
    return spS[a] < spS[b];
}
signed main()
{

    cin>>n>>m>>s>>t>>u>>v;
    u-- , v-- , t-- , s--;
    fore(i , m)
    {
        int a , b,c;
        cin>>a>>b>>c;
        a-- , b--;
        adj[a].pb({b , c});
        adj[b].pb({a , c});
    }
    spS = dijkstra(s) , spT = dijkstra(t) , spV = dijkstra(v) , spU = dijkstra(u);
    int ans = INF;
    vi vv;
    fore(i , n)
    {
        vv.pb(i);
    }
//    sort(all(vv) , cmp);
    for(auto x : vv)
    {
        if(spS[x]+spT[x] == spS[t])
            ans = min(ans , min(dfs0(x) ,dfs(x)) + spU[x]);
    }
    cout<<min(ans , spU[v])<<nl;
}

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