Submission #1051296

#	Time	Username	Problem	Language	Result	Execution time	Memory
1051296		vjudge1	Commuter Pass (JOI18_commuter_pass)	C++98	15 / 100	646 ms	64340 KiB

commuter_pass

#include <bits/stdc++.h>
// #define DEBUG 1
// #pragma GCC optimize("O3,unroll-loops")
// #pragma GCC target("avx2,bmi,bmi2,lzcnt,popcnt")
// #pragma GCC optimize("Ofast,no-stack-protector,unroll-loops,fast-math,O3")
// #pragma GCC target("sse,sse2,sse3,ssse3,sse4,popcnt,abm,avx,mmx,tune=native")
// #include <ext/pb_ds/detail/standard_policies.hpp>
// #include <ext/pb_ds/assoc_container.hpp>
using namespace std;
// using namespace __gnu_pbds;
// typedef tree<int,null_type,less<int>,rb_tree_tag,tree_order_statistics_node_update> ordered_set;
/* find_by_order() order_of_key() */
void __print(int x) {cerr << x;}
void __print(long x) {cerr << x;}
void __print(long long x) {cerr << x;}
void __print(unsigned x) {cerr << x;}
void __print(unsigned long x) {cerr << x;}
void __print(unsigned long long x) {cerr << x;}
void __print(float x) {cerr << x;}
void __print(double x) {cerr << x;}
void __print(long double x) {cerr << x;}
void __print(char x) {cerr << '\'' << x << '\'';}
void __print(const char *x) {cerr << '\"' << x << '\"';}
void __print(const string &x) {cerr << '\"' << x << '\"';}
void __print(bool x) {cerr << (x ? "true" : "false");}
 
template<typename T, typename V>
void __print(const pair<T, V> &x) {cerr << '{'; __print(x.first); cerr << ", "; __print(x.second); cerr << '}';}
template<typename T>
void __print(const T &x) {int f = 0; cerr << '{'; for (auto &i: x) cerr << (f++ ? ", " : ""), __print(i); cerr << "}";}
void _print() {cerr << "]\n";}
template <typename T, typename... V>
void _print(T t, V... v) {__print(t); if (sizeof...(v)) cerr << ", "; _print(v...);}
#ifdef DEBUG
#define dbg(x...) cerr << "\e[91m"<<__func__<<":"<<__LINE__<<" [" << #x << "] = ["; _print(x); cerr << "\e[39m" << endl;
#else
#define dbg(x...)
#endif
#define elif else if
#define pb push_back
#define fast cin.tie(nullptr); ios_base::sync_with_stdio(false);
#define all(x) (x).begin(), (x).end()
#define rall(x) (x).rbegin(), (x).rend()
#define str to_string
#define sz(x) int(x.size())
#define F first
#define S second
#define FOR(i, a, b) for (int i=a; i < (b); i++)
#define F0R(i, a) for (int i=0; i < (a); i++)
#define FORd(i, a, b) for (int i = (b) - 1; i >= a; i--)
#define F0Rd(i, a) for (int i = (a) - 1; i >= 0; i--)
#define watch(x) cout << #x << " <----  " << x << endl
mt19937 rng(chrono::steady_clock::now().time_since_epoch().count());
template<typename A, typename B>
inline bool umin(A& a, B b) {
    if (a > b) {
        a = b;
        return true;
    }
    return false;
}
 
template<typename A, typename B>
inline bool umax(A& a, B b) {
    if (a < b) {
        a = b;
        return true;
    }
    return false;
}
 
template<typename T>
T binpow(T b, T e, T m) {
    T r = 1;
    while(e > 0) {
        if(e & 1) r = r * b % m;
        b = b * b % m;
        e >>= 1;
    }
    return r;
}
using ll = long long;
using ld = long double;
using ull = unsigned long long;
inline ll rand(ll l, ll r) {
    return uniform_int_distribution<ll>(l, r)(rng);
}
const int N = 1e5 + 1;
const ll mod = 1e9 + 7;
const ll INF = 1e18;
ll n, m, k, q;
int h1[4] = {1, 0, 0, -1};
int h2[4] = {0, -1, 1, 0};
ll a[N];
bool check(int x, int y) {
    return (x >= 0 && y >= 0 && x < n && y < m);
}
int go(char c) {
    return c - '0';
}
set<pair<ll, ll>> adj[N];
/* Problems solved, rank evolved. */
int u, v;
int s, t;
int p[N];
ll d[N];
map<pair<int, int>, ll> mp;
void tourist() {
    // #ifndef ONLINE_JUDGE
    //     freopen("input.txt", "r", stdin);
    //     freopen("output.txt", "w", stdout);
    //     freopen("errors.txt", "w", stderr);
    // #endif
    cin >> n >> m;
    cin >> s >> t;
    cin >> u >> v;
    for(int i = 0; i < m; i++){
      ll f,g, c;
      cin >> f >> g >> c;
      adj[f].insert({g, c});
      adj[g].insert({f, c});
      mp[{f, g}] = c;
      mp[{g, f}] = c;
    }
    set<pair<ll, int>> pq;
    pq.insert({0, s});
    for(int i = 1; i <= n; i++) {
      d[i] = INF;
    }
    p[s] = -1;
    d[s] = 0;

    while(!pq.empty()){
      pair<ll, int> cur = *pq.begin();
      pq.erase(cur);
      for(auto i : adj[cur.S]){
        int to = i.F;
        int w = i.S;
        if(d[to] > d[cur.S] + w){
          pq.erase({d[to], to});
          d[to] = d[cur.S] + w;
          p[to] = cur.S;
          pq.insert({d[to], to});
        }
      }
    }
    ll d2[N];
    for(int i = 1; i<= n; i++){
      d2[i] = INF;
    }
    if(s == u){
      d2[t] = 0;
      
      pq.insert({0, t});
      vector<int> vert;
      while(!pq.empty()){
        pair<ll, int> cur = *pq.begin();
        pq.erase(cur);
        for(auto i : adj[cur.S]){
          int to = i.F;
          int w = i.S;
          if(d2[to] > d2[cur.S] + w){
            pq.erase({d2[to], to});
            d2[to] = d2[cur.S] + w;
            pq.insert({d2[to], to});
          }
        }
      }
      
      for(int i = 1; i <= n; i++){
        // cout << d[i] << ' ' << d2[i] << '\n';
        if(d[i] + d2[i] == d[n]){
          vert.pb(i);
          // cout << i << ' ';
        }
      }
      // cout << '\n';
      pq.insert({0, v});
      for(int i = 1; i <= n; i++) {
        d2[i] = INF;
      }
      d2[v] = 0;
      while(!pq.empty()){
        pair<ll, int> cur = *pq.begin();
        pq.erase(cur);
        for(auto i : adj[cur.S]){
          int to = i.F;
          int w = i.S;
          if(d2[to] > d2[cur.S] + w){
            pq.erase({d2[to], to});
            d2[to] = d2[cur.S] + w;
            pq.insert({d2[to], to});
          }
        }
      }
      ll mx = INF;
      for(int i : vert){
        // cout << d2[i] << ' ';
        mx = min(mx, d2[i]);
      }
      // cout << '\n';
      cout << mx << '\n';
      return;
    }
    
    // for(int i = 1; i <= n; ++i){
    //   cout << d[i] << ' ';
    // }
    // cout << d[t] << '\n';
    int cur = t;
    // map<int, int> mp2;
    while(p[cur] != -1){
      int x = p[cur];
      if(adj[x].find({cur, mp.at({x, cur})}) != adj[x].end()) {
        adj[x].erase({cur, mp.at({x, cur})});
      }
      if(adj[cur].find({x, mp.at({x,cur})}) != adj[cur].end()){
        adj[cur].erase({x, mp.at({x,cur})});
      }
      adj[x].insert({cur, 0});
      adj[cur].insert({x, 0});
      // assert((mp2.count(cur) == 0) && "cycle was found!!!");
      // mp2[cur] = 1;
      cur = x;
    }
    pq.insert({0, u});
    for(int i = 1; i <= n; i++) {
      d[i] = INF;
    }
    p[u] = -1;
    d[u] = 0;
    cout << '\n';
    // for(int i = 1; i <= n; ++i){
    //   cout << d[i] << ' ';
    // }
    // cout << '\n';
    // for(auto i : adj[u]){
    //   cout << i.F << ' ' << i.S << '\n';
    // }
    while(!pq.empty()){
      pair<ll, int> cur = *pq.begin();
      pq.erase(cur);
      for(auto i : adj[cur.S]){
        int to = i.F;
        int w = i.S;
        if(d[to] > d[cur.S] + w){
          // if(cur.S == 3 && to == 4){
          //   cout << "YES\n";
          // }
          pq.erase({d[to], to});
          d[to] = d[cur.S] + w;
          p[to] = cur.S;
          pq.insert({d[to], to});
        }
      }
    }
    cout << d[v] << '\n';
}

/*Give me some sunshine, give me some rain, its a beatifull day-ay-ay-ay...*/
int32_t main() {
    fast
    int tt = 1;
    // cin >> tt;
    while (tt--) {
        tourist();
    }
}

• Subtask 1: 0 / 16
• Subtask 2: 15 / 15
• Subtask 3: 0 / 24
• Subtask 4: 0 / 45