Submission #862212

#	Time	Username	Problem	Language	Result	Execution time	Memory
862212		green_gold_dog	Commuter Pass (JOI18_commuter_pass)	C++17	100 / 100	287 ms	29248 KiB

commuter_pass

//#pragma GCC optimize("Ofast")
//#pragma GCC target("avx,avx2,sse,sse2,sse3,ssse3,sse4,abm,popcnt,mmx")
#include <bits/stdc++.h>

using namespace std;

typedef long long ll;
typedef double db;
typedef long double ldb;
typedef complex<double> cd;

constexpr ll INF64 = 9'000'000'000'000'000'000, INF32 = 2'000'000'000, MOD = 1'000'000'007;
constexpr db PI = acos(-1);
constexpr bool IS_FILE = false, IS_TEST_CASES = false;

random_device rd;
mt19937 rnd32(rd());
mt19937_64 rnd64(rd());

template<typename T>
bool assign_max(T& a, T b) {
        if (b > a) {
                a = b;
                return true;
        }
        return false;
}

template<typename T>
bool assign_min(T& a, T b) {
        if (b < a) {
                a = b;
                return true;
        }
        return false;
}

template<typename T>
T square(T a) {
        return a * a;
}

template<>
struct std::hash<pair<ll, ll>> {
        ll operator() (pair<ll, ll> p) const {
                return ((__int128)p.first * MOD + p.second) % INF64;
        }
};

vector<ll> dist(ll v, vector<vector<pair<ll, ll>>>& arr) {
        vector<ll> d(arr.size(), INF64);
        priority_queue<pair<ll, ll>, vector<pair<ll, ll>>, greater<pair<ll, ll>>> pq;
        pq.emplace(0, v);
        d[v] = 0;
        while (!pq.empty()) {
                auto[nd, u] = pq.top();
                pq.pop();
                if (nd != d[u]) {
                        continue;
                }
                for (auto[i, di] : arr[u]) {
                        if (assign_min(d[i], nd + di)) {
                                pq.emplace(d[i], i);
                        }
                }
        }
        return d;
}

void dfs(ll v, vector<bool>& used, vector<vector<ll>>& tree, vector<ll>& ts) {
        used[v] = true;
        for (auto i : tree[v]) {
                if (!used[i]) {
                        dfs(i, used, tree, ts);
                }
        }
        ts.push_back(v);
}

void solve() {
        ll n, m, s, t, u, v;
        cin >> n >> m >> s >> t >> u >> v;
        s--;
        t--;
        u--;
        v--;
        vector<vector<pair<ll, ll>>> arr(n);
        for (ll i = 0; i < m; i++) {
                ll a, b, c;
                cin >> a >> b >> c;
                a--;
                b--;
                arr[a].emplace_back(b, c);
                arr[b].emplace_back(a, c);
        }
        vector<ll> ds = dist(s, arr), dt = dist(t, arr), du = dist(u, arr), dv = dist(v, arr);
        ll dst = ds[t];
        vector<vector<ll>> narr(n);
        for (ll i = 0; i < n; i++) {
                for (auto[j, c] : arr[i]) {
                        if (ds[i] + c + dt[j] == dst) {
                                narr[i].push_back(j);
                        }
                }
        }
        vector<ll> ts;
        vector<bool> used(n, false);
        for (ll i = 0; i < n; i++) {
                if (!used[i]) {
                        dfs(i, used, narr, ts);
                }
        }
        ll ans = du[v];
        vector<ll> dp = du;
        for (auto i : ts) {
                for (auto j : narr[i]) {
                        assign_min(dp[i], dp[j]);
                }
                assign_min(ans, dp[i] + dv[i]);
        }
        dp = dv;
        for (auto i : ts) {
                for (auto j : narr[i]) {
                        assign_min(dp[i], dp[j]);
                }
                assign_min(ans, dp[i] + du[i]);
        }
        cout << ans << '\n';
}

int main() {
        if (IS_FILE) {
                freopen("", "r", stdin);
                freopen("", "w", stdout);
        }
        ios_base::sync_with_stdio(false);
        cin.tie(0);
        cout.tie(0);
        ll t = 1;
        if (IS_TEST_CASES) {
                cin >> t;
        }
        for (ll i = 0; i < t; i++) {
                solve();
        }
}

Compilation message (stderr)

commuter_pass.cpp: In function 'int main()':
commuter_pass.cpp:133:24: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
  133 |                 freopen("", "r", stdin);
      |                 ~~~~~~~^~~~~~~~~~~~~~~~
commuter_pass.cpp:134:24: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
  134 |                 freopen("", "w", stdout);
      |                 ~~~~~~~^~~~~~~~~~~~~~~~~

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