Submission #549737

#	Time	Username	Problem	Language	Result	Execution time	Memory
549737		Soul234	Commuter Pass (JOI18_commuter_pass)	C++14	100 / 100	342 ms	20236 KiB

commuter_pass

#include<bits/stdc++.h>
using namespace std;

void DBG() { cerr << "]\n"; }
template<class H, class... T> void DBG(H h, T... t) {
    cerr << h; if(sizeof...(t)) cerr << ", ";
    DBG(t...);
}
#ifdef LOCAL
#define dbg(...) cerr << "[" << #__VA_ARGS__ << "]: [", DBG(__VA_ARGS__)
#else
#define dbg(...) 0
#endif // LOCAL

#define FOR(i,a,b) for(int i = (a) ; i<(b) ; i++)
#define F0R(i,a) FOR(i,0,a)
#define ROF(i,a,b) for(int i = (b)-1 ; i>=(a) ; i--)
#define R0F(i,a) ROF(i,0,a)
#define each(e,a) for(auto &e : (a))
#define sz(v) (int)(v).size()
#define all(v) (v).begin(),(v).end()
#define rall(v) (v).rbegin(),(v).rend()
#define pb push_back
#define tcT template<class T
#define nl "\n"

using ll = long long;
using vi = vector<int>;
using pi = pair<int,int>;
using str = string;
tcT> using V = vector<T>;
tcT> using pqg = priority_queue<T,vector<T>,greater<T>>;

void setIO(string NAME = "") {
    cin.tie(0)->sync_with_stdio(0);
    if(sz(NAME)) {
        freopen((NAME + ".inp").c_str(),"r",stdin);
        freopen((NAME + ".out").c_str(),"w",stdout);
    }
}

tcT> bool ckmin(T&a, const T&b) {
    return b < a ? a = b, 1 : 0;
}
const int MX = 1e5+5;
const ll INF = 1e18;
int N, M, s, t, u, v;
V<pi> adj[MX];
ll Dist[2][MX], dist[MX], dp[2][MX], ans = INF;

void gen(int src, int st) {
    memset(Dist[st], 0x3f, sizeof Dist[st]);
    pqg<pair<ll,int>> pq;
    pq.push({Dist[st][src] = 0, src});
    while(sz(pq)) {
        int ver = pq.top().second; ll dver = pq.top().first;
        pq.pop();
        if(dver != Dist[st][ver]) continue;
        each(ed, adj[ver]) {
            int nver = ed.first;
            ll ndver = dver + ed.second;
            if(ckmin(Dist[st][nver], ndver)) pq.push({Dist[st][nver], nver});
        }
    }
}

void ijk(int src, int dst) {
    memset(dist, 0x3f, sizeof dist);
    memset(dp, 0x3f, sizeof dp);
    pqg<pair<ll,int>> pq;
    pq.push({dist[src] = 0, src});
    dp[0][src] = Dist[0][src];
    dp[1][src] = Dist[1][src];
    while(sz(pq)) {
        int ver = pq.top().second; ll dver = pq.top().first;
        pq.pop();
        if(dver != dist[ver]) continue;
        each(ed, adj[ver]) {
            int nver = ed.first; ll dnver = dver + ed.second;
            if(ckmin(dist[nver], dnver)) {
                pq.push({dist[nver], nver});
                F0R(i,2) dp[i][nver] = min(dp[i][ver], Dist[i][nver]);
            }
            else if(dist[nver] == dnver && min(dp[0][ver], Dist[0][nver]) + min(dp[1][ver], Dist[1][nver]) <= dp[0][nver] + dp[1][nver]) {
                dp[0][nver] = min(Dist[0][nver], dp[0][ver]);
                dp[1][nver] = min(Dist[1][nver], dp[1][ver]);
            }
        }
    }
    ckmin(ans, dp[0][dst] + dp[1][dst]);
}

void solve() {
    cin>>N>>M>>s>>t>>u>>v;
    F0R(i,M) {
        int a,b,c;
        cin>>a>>b>>c;
        adj[a].pb({b,c});
        adj[b].pb({a,c});
    }
    gen(u, 0);
    ans = Dist[0][v];
    gen(v, 1);
    F0R(i,2) FOR(j,1,N+1) dbg(Dist[i][j], i, j);
    ijk(s, t); ijk(t, s);
    cout << ans << nl;

}

int main() {
    setIO();

    int t=1;
    //cin>>t;
    while(t-->0) {
        solve();
    }

    return 0;
}

Compilation message (stderr)

commuter_pass.cpp: In function 'void solve()':
commuter_pass.cpp:12:18: warning: statement has no effect [-Wunused-value]
   12 | #define dbg(...) 0
      |                  ^
commuter_pass.cpp:104:27: note: in expansion of macro 'dbg'
  104 |     F0R(i,2) FOR(j,1,N+1) dbg(Dist[i][j], i, j);
      |                           ^~~
commuter_pass.cpp: In function 'void setIO(std::string)':
commuter_pass.cpp:37:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   37 |         freopen((NAME + ".inp").c_str(),"r",stdin);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
commuter_pass.cpp:38:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   38 |         freopen((NAME + ".out").c_str(),"w",stdout);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

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