제출 #1248417

#	제출 시각	아이디	문제	언어	결과	실행 시간	메모리
1248417		dungnt	Commuter Pass (JOI18_commuter_pass)	C++20	100 / 100	282 ms	18888 KiB

commuter_pass

#include<bits/stdc++.h>
#define M 100004
#define ll long long
#define fi first
#define se second
#define pii pair<int, int>
#define plli pair<long long, int>
using namespace std;

const long long inf = 1e16;

int n, m;
int S, T, U, V;
vector<pii> adj[M];
vector<ll> dS, dT;

vector<ll> dijkstra(int s)
{
    vector<ll> d(n + 1, inf);
    priority_queue<plli, vector<plli>, greater<plli>> pq;
    d[s] = 0;
    pq.push({0, s});
    while(!pq.empty())
    {
        auto [du, u] = pq.top();
        pq.pop();
        if(du != d[u])  continue;
        for(pii &p : adj[u])
        {
            int v = p.fi, w = p.se;
            if(d[v] > du + w)
            {
                d[v] = du + w;
                pq.push({d[v], v});
            }
        }
    }
    return d;
}

bool cmp(int a, int b)
{
    return dS[a] > dS[b];
}

long long cal(vector<ll> &dU, vector<ll> &dV)
{
    vector<vector<int>> dag(n + 1);
    for(int u = 1; u <= n; u++)
    {
        for(pii &p: adj[u])
        {
            int v = p.fi, w = p.se;
            if(dS[u] + w + dT[v] == dS[T])
                dag[u].push_back(v);
        }
    }
    vector<int> g;
    for(int i = 1; i <= n; i++)
        g.push_back(i);
    sort(g.begin(), g.end(), cmp);
    vector<ll> dp(n + 1, inf);
    for(int x = 1; x <= n; x++)
        dp[x] = dV[x];
    for(int x : g)
    {
        for(int k : dag[x])
            dp[x] = min(dp[x], dp[k]);
    }
    long long ans = inf;
    for(int x = 1; x <= n; x++)
        ans = min(ans, dU[x] + dp[x]);
    return ans;
}

int main()
{
    ios_base::sync_with_stdio(0);
    cin.tie(0);     cout.tie(0);
    #define name "baitap"
    if(fopen(name".inp", "r"))
    {
        freopen(name".inp", "r", stdin);
        freopen(name".out", "w", stdout);
    }
    cin >> n >> m;
    cin >> S >> T >> U >> V;
    for(int i = 1; i <= m; i++)
    {
        int u, v, w;
        cin >> u >> v >> w;
        adj[u].push_back({v, w});
        adj[v].push_back({u, w});
    }
    dS = dijkstra(S);
    dT = dijkstra(T);
    auto dU = dijkstra(U);
    auto dV = dijkstra(V);
    cout << min(cal(dU, dV), cal(dV, dU));
}

컴파일 시 표준 에러 (stderr) 메시지

commuter_pass.cpp: In function 'int main()':
commuter_pass.cpp:83:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   83 |         freopen(name".inp", "r", stdin);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~
commuter_pass.cpp:84:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   84 |         freopen(name".out", "w", stdout);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~

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