Submission #1111024

#	Time	Username	Problem	Language	Result	Execution time	Memory
1111024		wibulord	Commuter Pass (JOI18_commuter_pass)	C++14	100 / 100	224 ms	28364 KiB

commuter_pass

#include <bits/stdc++.h>
#define endl '\n'
#define ll long long
#define fi first
#define se second
#define pb emplace_back
#define ii pair<ll, int>
#define MASK(i) (1LL << (i))
#define BIT(x, i) (((x) >> (i)) & 1)
#define sz(s) (int)((s).size())
#define all(a) a.begin(), a.end()
#define FOR(i, a, b) for (int i = (a), _b = (b); i <= _b; ++i)
#define F0R(i, b) for (int i = 0, _b = (b); i < _b; ++i)
#define FORd(i, a, b) for (int i = (a), _b = (b); i >= _b; --i)
#define F0Rd(i, b) for (int i = (b)-1; i >= 0; i--)
#define debug(...) " [" << #__VA_ARGS__ ": " << (__VA_ARGS__) << "] "
using namespace std;

template<typename T1,typename T2> bool ckmax(T1 &x,const T2 &y){if(x<y){x=y; return 1;} return 0;}
template<typename T1,typename T2> bool ckmin(T1 &x,const T2 &y){if(y<x){x=y; return 1;} return 0;}

const int MOD = (int)1e9 + 7;
const int mod = 998244353;
const int N = 2e5 + 10, M = 18;
const long long INF = (long long)4e18 + 11;

/*
     /\_/\
    (= ._.)
    / >?  \>$
*/

int n, m, s, t, u, v;
long long res;
long long d1[N], d2[N], d[N], F[N][2];
vector<ii> adj[N];
priority_queue<ii, vector<ii>, greater<ii>> pq;

void dijkstra1(int s, long long d[]){
    FOR(i, 1, n) d[i] = INF;
    d[s] = 0;
    while(sz(pq)) pq.pop();
    pq.push({d[s], s});
    while(sz(pq)){
        int u = pq.top().se;
        long long cost = pq.top().fi;
        pq.pop();
        if(d[u] < cost) continue;
        for(auto [v, w] : adj[u]) if(ckmin(d[v], d[u] + w)) pq.push({d[v], v});
    }
}

void dijkstra2(int s, int t){
    FOR(i, 1, n){
        d[i] = INF;
        F[i][0] = F[i][1] = INF;
    }
    d[s] = 0;
    while(sz(pq)) pq.pop();
    pq.push({d[s], s});
    F[s][0] = d1[s];
    F[s][1] = d2[s];
    while(sz(pq)){
        int u = pq.top().se;
        long long cost = pq.top().fi;
        pq.pop();
        if(d[u] < cost) continue;
        for(auto [v, w] : adj[u]){
            if(ckmin(d[v], d[u] + w)){
                pq.push({d[v], v});
                F[v][0] = min(F[u][0], d1[v]);
                F[v][1] = min(F[u][1], d2[v]);
            }
            else if(d[v] == d[u] + w && min(F[u][0], d1[v]) + min(F[u][1], d2[v]) < F[v][0] + F[v][1]){
                F[v][0] = min(F[u][0], d1[v]);
                F[v][1] = min(F[u][1], d2[v]);
            }
        }
    }
    res = min(res, F[t][0] + F[t][1]);
}

void sol(void){
    cin >> n >> m >> s >> t >> u >> v;
    FOR(i, 1, m){
        int u, v, w; cin >> u >> v >> w;
        adj[u].pb(v,w);
        adj[v].pb(u,w);
    }

    dijkstra1(u, d1); dijkstra1(v, d2);
    res = d1[v];
    dijkstra2(s, t);
    dijkstra2(t, s);
    cout << res << '\n';
}

signed main(void){
    #define TASK "nhap"
    if(fopen(TASK".inp", "r")){
        freopen(TASK".inp", "r", stdin);
        freopen(TASK".out", "w", stdout);
    }
    ios_base::sync_with_stdio(false); cin.tie(NULL); cout.tie(NULL);
    int t = 1;
//    cin >> t;
    while(t--) sol();
    cerr << "\nTime elapsed: " << 1000 * clock() / CLOCKS_PER_SEC << " ms\n";
}

Compilation message (stderr)

commuter_pass.cpp: In function 'void dijkstra1(int, long long int*)':
commuter_pass.cpp:49:18: warning: structured bindings only available with '-std=c++17' or '-std=gnu++17'
   49 |         for(auto [v, w] : adj[u]) if(ckmin(d[v], d[u] + w)) pq.push({d[v], v});
      |                  ^
commuter_pass.cpp: In function 'void dijkstra2(int, int)':
commuter_pass.cpp:68:18: warning: structured bindings only available with '-std=c++17' or '-std=gnu++17'
   68 |         for(auto [v, w] : adj[u]){
      |                  ^
commuter_pass.cpp: In function 'int main()':
commuter_pass.cpp:101:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
  101 |         freopen(TASK".inp", "r", stdin);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~
commuter_pass.cpp:102:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
  102 |         freopen(TASK".out", "w", stdout);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~

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