Submission #367213

#	Time	Username	Problem	Language	Result	Execution time	Memory
367213		piddddgy	Olympic Bus (JOI20_ho_t4)	C++11	0 / 100	1093 ms	10860 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][maxn];

// .fi = cost, .se = destination
multiset<pii> G[maxn];

multiset<int> mi[maxn][maxn];

int dist(int x, int y) {
    cerr << "go from " << x << " -> " << y << endl;
    for(int i = 1; i <= n; i++) {
        for(int j = 1; j <= n; j++) {
            if(i == j) {
                dis[i][j] = 0;
            } else {
                dis[i][j] = 1e18;
            }
        }
    }
    
    for(int i = 1; i <= n; i++) {
        for(int j = 1; j <= n; j++) {
            if(mi[i][j].empty()) continue;
            dis[i][j] = min(dis[i][j], *mi[i][j].begin());
        }
    }

    for(int rep = 1; rep <= 10; rep++)
    for(int k = 1; k <= n; k++) {
        for(int i = 1; i <= n; i++) {
            for(int j = 1; j <= n; j++) {
                dis[i][j] = min(dis[i][j], dis[i][k] + dis[k][j]);
            }
        }
    }

    for(int i = 1; i <= n; i++) {
        for(int j = 1; j <= n; j++) {
            if(dis[i][j] == 1e18) cout << "I ";
            else cerr << dis[i][j] << " ";
        }
        cerr << endl;
    }

    return dis[x][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;
        G[u[i]].emplace(c[i], v[i]);
        mi[u[i]][v[i]].emplace(c[i]);
    }

    watch(sz(G[2]))
    // watch(ree)
    int ans = 1e18;
    ans = min(ans, dist(1, n)+dist(n, 1));

    for(int i = 1; i <= m; i++) {
        cerr << "trying " << i << endl;
        // reverse
        mi[u[i]][v[i]].erase(mi[u[i]][v[i]].lower_bound(c[i]));
        mi[v[i]][u[i]].emplace(c[i]);

        int to = dist(1, n);
        int back = dist(n, 1);

        watch(to)
        watch(back)
        watch(d[i]+to+back)
        ans = min(ans, d[i] + to + back);

        // put back
        mi[v[i]][u[i]].erase(mi[v[i]][u[i]].lower_bound(c[i]));
        mi[u[i]][v[i]].emplace(c[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: 0 / 5
• Subtask 2: 0 / 11
• Subtask 3: 0 / 21
• Subtask 4: 0 / 63