Submission #595127

#	Time	Username	Problem	Language	Result	Execution time	Memory
595127		tamthegod	Evacuation plan (IZhO18_plan)	C++14	100 / 100	655 ms	73104 KiB

plan

#include<bits/stdc++.h>

#define int long long
#define pb push_back
#define fi first
#define se second
using namespace std;
using ll = long long;
using ld = long double;
using ull = unsigned long long;
mt19937 rng(chrono::steady_clock::now().time_since_epoch().count());
const int maxN = 5e5 + 5;
const int mod = 1e9 + 7;
const ll oo = 1e9;
int n, m;
int lab[maxN];
int d[maxN];
int id[maxN];
int q;
struct TQuery
{
    int s, t, id;
    int low, high, mid;
} qu[maxN];
int Findset(int u)
{
    return lab[u] < 0 ? u : lab[u] = Findset(lab[u]);
}
void Unite(int u, int v)
{
    int r = Findset(u), s = Findset(v);
    if(r == s) return;
    if(lab[r] > lab[s]) swap(r, s);
    lab[r] += lab[s];
    lab[s] = r;
}
struct TEdge
{
    int u, v, w;
} e[maxN];
struct TAdj
{
    int v, w;
};
vector<TAdj> adj[maxN];
int k, a[maxN];
struct TPQRect
{
    int vertex, dlab;
    bool operator < (const TPQRect& other) const
    {
        return other.dlab < dlab;
    }
    bool Valid() const
    {
        return d[vertex] == dlab;
    }
};
bool Relax(int x, int y, int w)
{
    if(d[y] > d[x] + w)
    {
        d[y] = d[x] + w;
        return true;
    }
    return false;
}
void Dijkstra()
{
    priority_queue<TPQRect> pq;
    memset(d, 3, sizeof d);
    for(int i=1; i<=k; i++)
    {
        d[a[i]] = 0;
        pq.push({a[i], 0});
    }
    do
    {
        TPQRect r = pq.top();
        pq.pop();
        if(!r.Valid()) continue;
        int u = r.vertex;
        for(TAdj a : adj[u])
        {
            if(Relax(u, a.v, a.w))
                pq.push({a.v, d[a.v]});
        }
    }
    while(!pq.empty());
}
void ReadInput()
{
    cin >> n >> m;
    for(int i=1; i<=m; i++)
    {
        int u, v, w;
        cin >> u >> v >> w;
        e[i] = {u, v, w};
        adj[u].pb({v, w});
        adj[v].pb({u, w});
    }
    cin >> k;
    for(int i=1; i<=k; i++) cin >> a[i];
    cin >> q;
    for(int i=1; i<=q; i++)
    {
        int s, t;
        cin >> s >> t;
        qu[i].s = s, qu[i].t = t, qu[i].id = i;
        qu[i].low = 1, qu[i].high = oo;
    }
}
bool chk(int s, int t, int val)
{
    memset(lab, -1, sizeof lab);
    for(int i=1; i<=m; i++)
        if(d[e[i].u] >= val && d[e[i].v] >= val) Unite(e[i].u, e[i].v);
    return Findset(s) == Findset(t);
}
void parallel_bs()
{
    memset(lab, -1, sizeof lab);
    for(int i=1; i<=q; i++) qu[i].mid = (qu[i].low + qu[i].high) / 2;
    sort(qu + 1, qu + q + 1, [](TQuery p, TQuery q)
    {
        return p.mid > q.mid;
    });
    int p = 1;
    for(int i=1; i<=q; i++)
    {
        while(p <= m && min(d[e[p].u], d[e[p].v]) >= qu[i].mid)
        {
            Unite(e[p].u, e[p].v);
            p++;
        }
        //cout << (Findset(qu[i].s) == Findset(qu[i].t));exit(0);
        if(Findset(qu[i].s) == Findset(qu[i].t)) qu[i].low = qu[i].mid + 1;
        else qu[i].high = qu[i].mid - 1;
    }
}
void Solve()
{
    Dijkstra();
    sort(e + 1, e + m + 1, [](TEdge p, TEdge q)
    {
        return min(d[p.u], d[p.v]) > min(d[q.u], d[q.v]);
    });
    for(int _=1; _<=30; _++) parallel_bs();
    sort(qu + 1, qu + q + 1, [](TQuery p, TQuery q)
    {
        return p.id < q.id;
    });
  //  cout << qu[1].high;return;
    for(int i=1; i<=q; i++) cout << qu[i].high << '\n';
}
int32_t main()
{
   // freopen("x.inp", "r", stdin);
    ios_base::sync_with_stdio(false);
    cin.tie(nullptr);
    ReadInput();
    Solve();
}

• Subtask 1: 10 / 10
• Subtask 2: 13 / 13
• Subtask 3: 12 / 12
• Subtask 4: 19 / 19
• Subtask 5: 46 / 46