Submission #1067369

#	Time	Username	Problem	Language	Result	Execution time	Memory
1067369		LinhLewLew	Commuter Pass (JOI18_commuter_pass)	C++17	100 / 100	184 ms	25088 KiB

commuter_pass

// PhuThuyRuntime <3
// A secret makes a woman woman

#include <bits/stdc++.h>

using namespace std;

#define eb emplace_back
#define ef emplace_front
#define pb push_back
#define pf push_front
#define all(v) v.begin(), v.end()
#define ins insert
#define lb lower_bound
#define ub upper_bound
#define fo(i, l, r) for(int i = l; i <= r; i++)
#define foi(i, l, r) for(int i = l; i >= r; i--)
#define elif else if
#define el cout << "\n";
#define pii pair<int, int>
#define pli pair<ll, int>
#define pll pair<ll, ll>
#define pil pair<int, ll>
#define fi first
#define se second
#define in(x) freopen(x, "r", stdin)
#define out(x) freopen(x, "w", stdout)
#define ll long long
#define ull unsigned long long
#define pob pop_back
#define bs binary_search
#define vi vector<int>
#define vii vector<pair<int, int>>
#define getbit(i, j) (i >> j) & 1
#define offbit(i, j) (1 << j) ^ i
#define onbit(i, j) (1 << j) | i
const int N = 1e5 + 2;
const ll mod = 1e9 + 7;
const int inf = INT_MAX;
const int base = 31;
const long double EPS = 1e-9;
const long double pi = acos(-1.0);
int n, m, S, T, U, V;
vii adj[N];
vector<pair<pii, int>> edges;
void inp(){
     cin >> n >> m >> S >> T >> U >> V;
     fo(i, 1, m){
          int u, v, c; cin >> u >> v >> c;
          edges.push_back({{u, v}, c});
          adj[u].eb(v, c);
          adj[v].eb(u, c);
     }
}
ll dp[N], dpU[N], dpV[N];
void dij(int start, ll DP[]){
     fo(i, 1, n) DP[i] = 1e18;
     priority_queue<pli, vector<pli>, greater<pli>> q;
     DP[start] = 0;
     q.push({0, start});
     while(!q.empty()){
          ll val = q.top().fi;
          int u = q.top().se;
          q.pop();
          if(val != DP[u]) continue;
          for(auto [v, w] : adj[u]){
               if(DP[v] > DP[u] + w){
                    DP[v] = DP[u] + w;
                    q.push({DP[v], v});
               }
          }
     }
}
ll tot = 1e18;
int exist[N];
void predfs(int u){
     if(exist[u] != -1) return;
     bool ok = (u == T);
     for(auto [v, w] : adj[u]){
          predfs(v);
          ok = ok || exist[v];
     }
     exist[u] = ok;
}
ll ans[N];
void dfs(int u, ll dp1[], ll dp2[]){
     if(ans[u] != -1) return;
     ans[u] = 1e18;
     if(exist[u]) ans[u] = dp2[u];
     for(auto [v, w] : adj[u]){
          dfs(v, dp1, dp2);
          ans[u] = min(ans[u], ans[v]);
     }
     tot = min(tot, dp1[u] + ans[u]);
}
void sol(){
     dij(S, dp);
//     fo(i, 1, n) cout << dp[i] << ' ';
//     el
     dij(U, dpU);
     dij(V, dpV);
     tot = dpU[V];
     fo(i, 1, n) adj[i].clear();
     for(auto [it, w] : edges){
          auto [u, v] = it;
          if(dp[u] == dp[v] + w){
               adj[v].eb(u, w);
//               cout << v << ' ' << u, el
          }
          if(dp[v] == dp[u] + w){
               adj[u].eb(v, w);
//               cout << u << ' ' << v, el
          }
     }
     memset(exist, -1, sizeof(exist));
     predfs(S);
     memset(ans, -1, sizeof(ans));
     dfs(S, dpU, dpV);
     memset(ans, -1, sizeof(ans));
     dfs(S, dpV, dpU);
     cout << tot;
}
int main(){
     ios_base::sync_with_stdio(false);
     cin.tie(NULL);
     inp();
     sol();
     return 0;
}

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