Submission #552262

#	Time	Username	Problem	Language	Result	Execution time	Memory
552262		Soul234	Evacuation plan (IZhO18_plan)	C++14	0 / 100	431 ms	57716 KiB

plan

#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, LG = 18;
int N, M, K, Q, par[MX][LG], dep[MX];
ll dist[MX], jmp[MX][LG];
V<pi> adj[MX], eds;
vi tr[MX];

struct UF {
    vi e;
    UF(int n) : e(n, -1) {}
    int find(int x) { return e[x] < 0 ? x : e[x] = find(e[x]); }
    bool sameSet(int a, int b) { return find(a) == find(b); }
    bool join(int a, int b) {
        a = find(a), b = find(b);
        if(a == b) return false;
        if(e[a] > e[b]) swap(a,b);
        e[a] += e[b]; e[b] = a;
        return true;
    }
};

void dfs(int u, int p, int d = 0) {
    par[u][0] = p;
    jmp[u][0] = min(dist[u], dist[p]);
    dep[u] = d;
    each(v, tr[u]) if(v != p) {
        dfs(v, u, d+1);
    }
}

pair<int,ll> Jmp(int u, int d) {
    pair<int,ll> ans = {u, dist[u]};
    F0R(i,LG) if(d>>i&1) {
        ans = {par[ans.first][i], min(ans.second, jmp[ans.first][i])};
    }
    return ans;
}

ll get_ans(int s, int t) {
    if(dep[s] < dep[t]) swap(s,t);
    pair<int,ll> tmp = Jmp(s, dep[s] - dep[t]);
    ll ans = tmp.second;
    s = tmp.first;
    R0F(i,LG) if(par[s][i] != par[t][i]) {
        ans = min({ans, jmp[s][i], jmp[t][i]});
        s = par[s][i]; t = par[t][i];
    }
    return min({ans, jmp[s][0], jmp[t][0]});
}

void solve() {
    cin>>N>>M;
    F0R(i,M) {
        int u,v,w;
        cin>>u>>v>>w;
        adj[u].pb({v,w});
        adj[v].pb({u,w});
        eds.pb({u,v});
    }
    memset(dist, 0x3f, sizeof dist);
    cin>>K;
    pqg<pair<ll,int>> pq;
    F0R(i,K) {
        int u; cin>>u;
        pq.push({dist[u] = 0, u});
    }
    while(sz(pq)) {
        ll du = pq.top().first;
        int u = pq.top().second;
        pq.pop();
        if(du != dist[u]) continue;
        each(ed, adj[u]) {
            int v = ed.first;
            ll dv = du + ed.second;
            if(ckmin(dist[v], dv)) pq.push({dist[v], v});
        }
    }
    UF dsu(N+1);
    sort(all(eds), [&](const pi&a, const pi&b){ return min(dist[a.first], dist[a.second]) > min(dist[b.first], dist[b.second]); });
    F0R(i,sz(eds)) {
        if(dsu.join(eds[i].first, eds[i].second)) {
            tr[eds[i].first].pb(eds[i].second);
            tr[eds[i].second].pb(eds[i].first);
        }
    }
    dfs(1,1);
    FOR(j,1,LG) FOR(i,1,N+1) {
        par[i][j] = par[par[i][j-1]][j-1];
        jmp[i][j] = min(jmp[i][j-1], jmp[par[i][j-1]][j-1]);
    }
    cin>>Q;
    while(Q--) {
        int s, t;
        cin>>s>>t;
        cout << get_ans(s, t) << nl;
    }
}

int main() {
    setIO();

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

    return 0;
}

Compilation message (stderr)

plan.cpp: In function 'void setIO(std::string)':
plan.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);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
plan.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: 0 / 10
• Subtask 2: 0 / 13
• Subtask 3: 0 / 12
• Subtask 4: 0 / 19
• Subtask 5: 0 / 46