Submission #1199667

#	Time	Username	Problem	Language	Result	Execution time	Memory
1199667		InvMOD	버스 (JOI14_bus)	C++17	100 / 100	136 ms	13996 KiB

bus

#include<bits/stdc++.h>

using namespace std;

#define fi first
#define se second
#define pb push_back
#define eb emplace_back

#define vi vector<int>
#define pi pair<int,int>
#define sz(v) (int)(v).size()
#define all(v) (v).begin(), (v).end()
#define compact(v) (v).erase(unique(all(v)), (v).end())

template<class T> using upq = priority_queue<T, vector<T>, greater<T>>;
template<class T> int lwrbound(const vector<T>& a, const T& b, const int s = 0){return int(lower_bound(s + all(a), b) - a.begin());}
template<class T> int uprbound(const vector<T>& a, const T& b, const int s = 0){return int(upper_bound(s + all(a), b) - a.begin());}

#define FOR(i, a, b) for(int i = (a); i <= (b); i++)
#define ROF(i, a, b) for(int i = (a); i >= (b); i--)
#define sumof(x) accumulate(all(x), 0ll)
#define dbg(x) "[" << #x " = " << (x) << "]"
#define el "\n"

using ll = long long;
using ld = long double;

template<class T> bool ckmx(T& a, const T b){return (a < b ? a = b, true : false);}
template<class T> bool ckmn(T& a, const T b){return (a > b ? a = b, true : false);}

const int N = 2e5 + 5;
const int MOD = 1e9 + 7;
const ll INF = numeric_limits<ll>::max() / 8;

struct Edge{
    int u,v,x,y;

    Edge(int u = 0, int v = 0, int x = 0, int y = 0): u(u), v(v), x(x), y(y) {}

    bool operator < (const Edge& q) const{
        return x > q.x;
    }

    // greedy x:

    /*
        if x[u[1]] > y[v[1]] -> break and wait for a better
        if x[u[1]] < y[v[1]] -> we can sure that this is the optimal answer

        because if x[u[2]] < y[v[1]] too, it is not optimal as taking x[u[1]] (u[1] has bigger x than u[2])
    */
};

struct Node{
    int x, time, from;

    Node(int x = 0, int time = 0, int from = 0): x(x), time(time), from(from) {}

    bool operator < (const Node& q) const{
        return time > q.time;
    }
};

void Main()
{
    int n,m; cin >> n >> m;

    vector<Edge> E; vector<vi> adj(n + 1, vi());
    for(int i = 0; i < m; i++){
        int u,v,x,y; cin >> u >> v >> x >> y;

        E.eb(u, v, x, y);
        adj[u].eb(i);
    }

    vector<int> ptr(n + 1, 0);
    for(int i = 1; i <= n; i++){
        sort(all(adj[i]), [&](int x, int y){return E[x] < E[y];});
    }

    vector<pair<int,int>> best;

    priority_queue<Node> pq;
    for(int id : adj[1]){
        int curMin = E[id].x, curMax = 2e9;

        pq.push(Node(E[id].v, E[id].y, id));
        while(sz(pq)){
            Node e = pq.top(); pq.pop();

            int x = e.x, ctime = e.time;
            if(x != n){
                while(ptr[x] < sz(adj[x])){
                    Edge ce = E[adj[x][ptr[x]]];
                    if(ctime <= ce.x){
                        pq.push(Node(ce.v, ce.y, adj[x][ptr[x]]));
                        ++ptr[x];
                    }
                    else break;
                }
            }
            else{
                curMax = min(curMax, ctime);
            }
        }
        best.eb(curMax, curMin);
    }

    sort(all(best)); // basic
    for(int i = 1; i < sz(best); i++){
        ckmx(best[i].se, best[i - 1].se);
    }

    int q; cin >> q;
    while(q--){
        int last; cin >> last;

        int p = uprbound(best, pi(last, 2e9)) - 1;
        if(p < 0){
            cout << "-1\n";
        }
        else{
            cout << best[p].se << el;
        }
    }
}

int32_t main()
{
    ios_base::sync_with_stdio(0);
    cin.tie(0); cout.tie(0);

    #define name "InvMOD"
    if(fopen(name".INP", "r")){
        freopen(name".INP", "r", stdin);
        freopen(name".OUT", "w", stdout);
    }

    int t = 1; while(t--) Main();
    return 0;
}

Compilation message (stderr)

bus.cpp: In function 'int32_t main()':
bus.cpp:136:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
  136 |         freopen(name".INP", "r", stdin);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~
bus.cpp:137:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
  137 |         freopen(name".OUT", "w", stdout);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~

• Subtask 1: 20 / 20
• Subtask 2: 15 / 15
• Subtask 3: 15 / 15
• Subtask 4: 50 / 50