Submission #1300812

#	Time	Username	Problem	Language	Result	Execution time	Memory
1300812		the_commando_x	Ferries (NOI13_ferries)	C++17	40 / 40	180 ms	31860 KiB

ferries

// #pragma GCC optimize("O3")
#include <bits/stdc++.h>

using namespace std;

using vi = vector<int>;
using vvi = vector<vi>;
using vvvi = vector<vvi>;

using pii = pair<int, int>;
using vii = vector<pii>;
using vvii = vector<vii>;

using l = long long;
using vl = vector<l>;
using vvl = vector<vl>;
using vvvl = vector<vvl>;

using pll = pair<l, l>;
using vll = vector<pll>;
using vvll = vector<vll>;

using d = double;
using vd = vector<d>;
using vvd = vector<vd>;
using vvvd = vector<vvd>;

using ld = long double;
using vld = vector<ld>;
using vvld = vector<vld>;
using vvvld = vector<vvld>;

using vb = vector<bool>;
using vvb = vector<vb>;
using pbb = pair<bool, bool>;
using vbb = vector<pbb>;

#define ff first
#define ss second

#define pb push_back
#define eb emplace_back
#define all(x) (x).begin(), (x).end()
#define rall(x) (x).rbegin(), (x).rend()
#define sz(x) (int)(x).size()

void setIO(string name = "")
{
    ios_base::sync_with_stdio(0);
    cin.tie(0);
    if (!name.empty())
    {
        (void)freopen((name + ".in").c_str(), "r", stdin);
        (void)freopen((name + ".out").c_str(), "w", stdout);
    }
}

const ld pi = 3.14159265358979323846;

const l LINF = 1e18;
const l INF = 1e9;

const l MOD = 1e9 + 7;
// const l MOD = 998244353;

const l MAXN = 2e5 + 5;

void solve()
{
    int n, m;
    cin >> n >> m;

    vvii adj(n);
    vvl cost(n), dest(n), rev(n);

    for (int i = 0; i < m; ++i)
    {
        int a, b, c;
        cin >> a >> b >> c;

        adj[--a].pb({--b, c});
        cost[a].pb(c);
        dest[a].pb(b), rev[b].pb(a);
    }

    for (int u = 0; u < n; ++u)
        sort(all(cost[u]));

    vl dp(n, LINF), good(n, 0);

    vb safe(n, false);

    priority_queue<pll, vll, greater<pll>> q;

    dp[n - 1] = 0, safe[n - 1] = true, q.push({0, n - 1});

    while (q.size())
    {
        auto [cur, u] = q.top();
        q.pop();

        safe[u] = true;

        if (cur != dp[u])
            continue;

        for (auto v : rev[u])
        {
            if (safe[v])
                continue;

            l k = ++good[v], deg = cost[v].size();

            l forced = cost[v][deg - k];

            l newcost = forced + dp[u];

            if (newcost < dp[v])
                dp[v] = newcost, q.push({newcost, v});
        }
    }

    cout << dp[0];
}

int main()
{
    setIO("");

#ifndef ONLINE_JUDGE
    // setIO("filename");
#endif

    int t = 1;
    // cin >> t;
    while (t--)
        solve();

    return 0;
}

Compilation message (stderr)

ferries.cpp: In function 'void setIO(std::string)':
ferries.cpp:53:22: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   53 |         (void)freopen((name + ".in").c_str(), "r", stdin);
      |               ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
ferries.cpp:54:22: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   54 |         (void)freopen((name + ".out").c_str(), "w", stdout);
      |               ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

• Subtask 1: 7 / 7
• Subtask 2: 10 / 10
• Subtask 3: 11 / 11
• Subtask 4: 12 / 12