Submission #367221

#	Time	Username	Problem	Language	Result	Execution time	Memory
367221		piddddgy	Olympic Bus (JOI20_ho_t4)	C++11	5 / 100	113 ms	10220 KiB

ho_t4

#include <bits/stdc++.h>
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>
using namespace std;
using namespace __gnu_pbds;
#define cerr if(false) cerr
#define watch(x) cerr << (#x) << " is " << (x) << endl;
#define endl '\n'
#define ld long double
#define int long long
#define pii pair<int, int>
#define fi first
#define se second
#define sz(a) (int)(a).size()
#define all(x) (x).begin(), (x).end()
    
const int maxn = 250;
const int maxm = 50500;
    
int n, m;
int u[maxm], v[maxm], c[maxm], d[maxm];
int dis[maxn];
    
// .fi = cost, .se = destination
multiset<pii> G[maxn];
    
int dist(int x, int y) {
    cerr << "go from " << x << " -> " << y << endl;
    for(int i = 1; i <= n; i++) {
        dis[i] = 1e18;
    }
    watch(sz(G[2]))
    
    priority_queue<pii> pq;
    dis[x] = 0;
    pq.push({0, x});
    
    while(!pq.empty()) {
        pii S = pq.top(); pq.pop();
        cerr << "on " << S.se << endl;
    
        S.fi *= -1;
    
        for(pii e: G[S.se]) {
            cerr << "edge " << e.fi << " " << e.se << endl;
            if(dis[e.se] > S.fi+e.fi) {
                cerr << "pushing " << e.se << endl;
                dis[e.se] = S.fi+e.fi;
                pq.push({-dis[e.se], e.se});
            }
        }
    }
    
    if(m > 1000 and dis[y] != 1e18) {
        assert(dis[y] == 0);
    }
    return dis[y];
}
    
signed main() {
    ios::sync_with_stdio(0);
    cin.tie(0);
    
    cin >> n >> m;
    
    for(int i = 1; i <= m; i++) {
        cin >> u[i] >> v[i] >> c[i] >> d[i];
    
        cerr << "going from " << u[i] << " to " << v[i] << " w cost " << c[i] << endl;

        if(m <= 1000) {
            G[u[i]].emplace(c[i], v[i]);
        } else {
            if(i%2 == 1) {
                G[u[i]].emplace(c[i], v[i]);
            } else {
                G[v[i]].emplace(c[i], u[i]);
            }
        }
    }
    
    watch(sz(G[2]))
    // watch(ree)
    int ans = 1e18;
    ans = min(ans, dist(1, n)+dist(n, 1));

    if(m <= 1000)
    for(int i = 1; i <= m; i++) {
        cerr << "trying " << i << endl;
        // reverse
        G[u[i]].erase(G[u[i]].lower_bound({c[i], v[i]}));
        G[v[i]].emplace(c[i], u[i]);
    
        int to = dist(1, n);
        int back = dist(n, 1);
    
        watch(to)
        watch(back)
        ans = min(ans, d[i] + to + back);
        // put back
        G[v[i]].erase(G[v[i]].lower_bound({c[i], u[i]}));
        G[u[i]].emplace(c[i], v[i]);
        cerr << endl;
    }
    
    if(ans == 1e18) {
        cout << -1 << endl;
    } else {
        cout << ans << endl;
    }
}
    
/*
    
simulate inverting each edge
    
4 5
1 2 4 4
1 3 2 1
4 3 1 2
4 1 6 1
2 4 2 5
-> 10
    
4 10
1 2 4 4
1 2 4 4
1 3 2 1
1 3 2 1
4 3 1 2
4 3 1 2
4 1 6 1
4 1 6 1
2 4 2 5
2 4 2 5
-> 10
    
4 4
1 2 0 4
1 3 0 1
4 3 0 2
4 1 0 1
-> 2
    
4 5
1 2 4 4
1 3 2 4
4 3 1 5
4 1 6 1
2 4 2 5
-> 12
    
4 5
2 1 4 4
1 3 2 1
4 3 1 2
4 3 6 1
2 4 2 5
-> -1
    
Did you read the bounds?
Did you make typos?
Are there edge cases (N=1?)
Are array sizes proper?
Integer overflow?
DS reset properly between test cases?
Is using long longs causing TLE?
Are you using floating points?
*/

• Subtask 1: 5 / 5
• Subtask 2: 0 / 11
• Subtask 3: 0 / 21
• Subtask 4: 0 / 63