oj.uz

Submission #922403

# Submission time Handle Problem Language Result Execution time Memory
922403 2024-02-05T13:25:25 Z GrindMachine Olympic Bus (JOI20_ho_t4) C++17
16 / 100
 1000 ms 6748 KB 
#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;

template<typename T> using Tree = tree<T, null_type, less<T>, rb_tree_tag, tree_order_statistics_node_update>;
typedef long long int ll;
typedef long double ld;
typedef pair<int,int> pii;
typedef pair<ll,ll> pll;

#define fastio ios_base::sync_with_stdio(false); cin.tie(NULL)
#define pb push_back
#define endl '\n'
#define sz(a) (int)a.size()
#define setbits(x) __builtin_popcountll(x)
#define ff first
#define ss second
#define conts continue
#define ceil2(x,y) ((x+y-1)/(y))
#define all(a) a.begin(), a.end()
#define rall(a) a.rbegin(), a.rend()
#define yes cout << "Yes" << endl
#define no cout << "No" << endl

#define rep(i,n) for(int i = 0; i < n; ++i)
#define rep1(i,n) for(int i = 1; i <= n; ++i)
#define rev(i,s,e) for(int i = s; i >= e; --i)
#define trav(i,a) for(auto &i : a)

template<typename T>
void amin(T &a, T b) {
    a = min(a,b);
}

template<typename T>
void amax(T &a, T b) {
    a = max(a,b);
}

#ifdef LOCAL
#include "debug.h"
#else
#define debug(x) 42
#endif

/*



*/

const int MOD = 1e9 + 7;
const int N = 200 + 5;
const int inf1 = int(1e9) + 5;
const ll inf2 = ll(1e18) + 5;
const int M = 5e4 + 5;

vector<array<ll,3>> adj[N];
vector<pll> adj2[N];
vector<bool> bridge(M);
vector<bool> vis(N);
vector<ll> tin(N), low(N);
ll timer = 1;

void dfs1(ll u, ll p){
    vis[u] = 1;
    tin[u] = low[u] = timer++;

    for(auto [v,id] : adj2[u]){
        if(v == p) conts;
        if(vis[v]){
            amin(low[u],tin[v]);
        }
        else{
            dfs1(v,u);
            amin(low[u],low[v]);
            if(low[v] > tin[u]){
                bridge[id] = 1;
            }
        }
    }
}

void dfs2(ll u, ll p, ll ignore){
    vis[u] = 1;
    for(auto [v,id] : adj2[u]){
        if(vis[v]) conts;
        if(id == ignore) conts;
        dfs2(v,u,ignore);
    }
}

void solve(int test_case)
{
    ll n,m; cin >> n >> m;
    vector<array<ll,4>> edges(m+5);

    rep1(i,m){
        ll u,v,w,d; cin >> u >> v >> w >> d;
        adj[u].pb({v,w,i}), adj[v].pb({u,w,i});
        edges[i] = {u,v,w,d};
    }

    auto dijkstra = [&](ll s, ll flipped){
        vector<ll> dis(n+5,inf2);
        dis[s] = 0;
        rep1(i,n) vis[i] = 0;

        rep1(iter,n){
            pll best = {inf2,inf2};
            rep1(u,n){
                if(vis[u]) conts;
                pll px = {dis[u],u};
                amin(best,px);
            }

            ll u = best.ss;
            vis[u] = 1;

            for(auto [v,w,id] : adj[u]){
                if(id != flipped){
                    if(edges[id][0] == u){
                        amin(dis[v],dis[u]+w);
                    }
                }
                else{
                    if(edges[id][0] == v){
                        amin(dis[v],dis[u]+w);
                    }
                }
            }
        }

        return dis;
    };

    auto dijkstra_rev = [&](ll s){
        vector<ll> dis(n+5,inf2);
        dis[s] = 0;
        rep1(i,n) vis[i] = 0;

        rep1(iter,n){
            pll best = {inf2,inf2};
            rep1(u,n){
                if(vis[u]) conts;
                pll px = {dis[u],u};
                amin(best,px);
            }

            ll u = best.ss;
            vis[u] = 1;

            for(auto [v,w,id] : adj[u]){
                if(edges[id][0] == v){
                    amin(dis[v],dis[u]+w);
                }
            }
        }

        return dis;
    };

    auto dis1 = dijkstra(1,-1);
    auto disn = dijkstra(n,-1);
    auto dis1_rev = dijkstra_rev(1);
    auto disn_rev = dijkstra_rev(n);

    rep1(u,n){
        for(auto [v,w,id] : adj[u]){
            if(edges[id][0] == u){
                if(dis1[u]+w == dis1[v]){
                    adj2[u].pb({v,id});
                }
            }
        }
    }

    auto go = [&](ll s){
        fill(all(vis),0);
        dfs2(s,-1,-1);
        ll reachable = count(all(vis),1);

        rep1(i,m){
            fill(all(vis),0);
            dfs2(s,-1,i);
            ll cnt = count(all(vis),1);
            if(cnt != reachable){
                bridge[i] = 1;
            }
        }
    };

    go(1);

    rep1(i,n) adj2[i].clear();

    rep1(u,n){
        for(auto [v,w,id] : adj[u]){
            if(edges[id][0] == u){
                if(disn[u]+w == disn[v]){
                    adj2[u].pb({v,id});
                }
            }
        }
    }

    timer = 1;
    fill(all(vis),0);
    go(n);

    assert(count(all(bridge),1) <= 2*n);

    ll ans = inf2;
    amin(ans,dis1[n]+disn[1]);

    rep1(i,m){
        auto [u,v,w,d] = edges[i];
        if(bridge[i]){
            ll cost = d+dijkstra(1,i)[n]+dijkstra(n,i)[1];
            amin(ans,cost);
        }
        else{
            ll sp_1_n = min(dis1[n],dis1[v]+w+disn_rev[u]);
            ll sp_n_1 = min(disn[1],disn[v]+w+dis1_rev[u]);
            ll cost = d+sp_1_n+sp_n_1;
            amin(ans,cost);
            if(cost == 1){
                debug(i);
                debug(sp_1_n);
                debug(sp_n_1);
                debug(disn[1]);
            }
        }
    }

    if(ans == inf2) ans = -1;
    cout << ans << endl;
}

int main()
{
    fastio;

    int t = 1;
    // cin >> t;

    rep1(i, t) {
        solve(i);
    }

    return 0;
}

Compilation message

ho_t4.cpp: In function 'void solve(int)':
ho_t4.cpp:46:18: warning: statement has no effect [-Wunused-value]
   46 | #define debug(x) 42
      |                  ^~
ho_t4.cpp:231:17: note: in expansion of macro 'debug'
  231 |                 debug(i);
      |                 ^~~~~
ho_t4.cpp:46:18: warning: statement has no effect [-Wunused-value]
   46 | #define debug(x) 42
      |                  ^~
ho_t4.cpp:232:17: note: in expansion of macro 'debug'
  232 |                 debug(sp_1_n);
      |                 ^~~~~
ho_t4.cpp:46:18: warning: statement has no effect [-Wunused-value]
   46 | #define debug(x) 42
      |                  ^~
ho_t4.cpp:233:17: note: in expansion of macro 'debug'
  233 |                 debug(sp_n_1);
      |                 ^~~~~
ho_t4.cpp:46:18: warning: statement has no effect [-Wunused-value]
   46 | #define debug(x) 42
      |                  ^~
ho_t4.cpp:234:17: note: in expansion of macro 'debug'
  234 |                 debug(disn[1]);
      |                 ^~~~~

Subtask #1
5.0 / 5.0

# Verdict Execution time Memory Grader output
1 Correct 6 ms 604 KB Output is correct
2 Correct 1 ms 348 KB Output is correct
3 Correct 56 ms 348 KB Output is correct
4 Correct 56 ms 604 KB Output is correct
5 Correct 3 ms 604 KB Output is correct
6 Correct 3 ms 516 KB Output is correct
7 Correct 0 ms 348 KB Output is correct
8 Correct 0 ms 344 KB Output is correct
9 Correct 1 ms 348 KB Output is correct
10 Correct 44 ms 604 KB Output is correct
11 Correct 59 ms 604 KB Output is correct
12 Correct 53 ms 600 KB Output is correct
13 Correct 25 ms 600 KB Output is correct
14 Correct 44 ms 600 KB Output is correct
15 Correct 41 ms 344 KB Output is correct
16 Correct 37 ms 604 KB Output is correct

Subtask #2
11.0 / 11.0

# Verdict Execution time Memory Grader output
1 Correct 142 ms 5464 KB Output is correct
2 Correct 158 ms 6240 KB Output is correct
3 Correct 141 ms 5976 KB Output is correct
4 Correct 7 ms 604 KB Output is correct
5 Correct 4 ms 604 KB Output is correct
6 Correct 2 ms 348 KB Output is correct
7 Correct 1 ms 348 KB Output is correct
8 Correct 0 ms 348 KB Output is correct
9 Correct 98 ms 6388 KB Output is correct
10 Correct 96 ms 6380 KB Output is correct
11 Correct 121 ms 6232 KB Output is correct
12 Correct 123 ms 6232 KB Output is correct
13 Correct 119 ms 6236 KB Output is correct
14 Correct 114 ms 6748 KB Output is correct

Subtask #3
0 / 21.0

# Verdict Execution time Memory Grader output
1 Correct 7 ms 604 KB Output is correct
2 Correct 9 ms 524 KB Output is correct
3 Execution timed out 1064 ms 4956 KB Time limit exceeded
4 Halted 0 ms 0 KB -

Subtask #4
0 / 63.0

# Verdict Execution time Memory Grader output
1 Correct 6 ms 604 KB Output is correct
2 Correct 1 ms 348 KB Output is correct
3 Correct 56 ms 348 KB Output is correct
4 Correct 56 ms 604 KB Output is correct
5 Correct 3 ms 604 KB Output is correct
6 Correct 3 ms 516 KB Output is correct
7 Correct 0 ms 348 KB Output is correct
8 Correct 0 ms 344 KB Output is correct
9 Correct 1 ms 348 KB Output is correct
10 Correct 44 ms 604 KB Output is correct
11 Correct 59 ms 604 KB Output is correct
12 Correct 53 ms 600 KB Output is correct
13 Correct 25 ms 600 KB Output is correct
14 Correct 44 ms 600 KB Output is correct
15 Correct 41 ms 344 KB Output is correct
16 Correct 37 ms 604 KB Output is correct
17 Correct 142 ms 5464 KB Output is correct
18 Correct 158 ms 6240 KB Output is correct
19 Correct 141 ms 5976 KB Output is correct
20 Correct 7 ms 604 KB Output is correct
21 Correct 4 ms 604 KB Output is correct
22 Correct 2 ms 348 KB Output is correct
23 Correct 1 ms 348 KB Output is correct
24 Correct 0 ms 348 KB Output is correct
25 Correct 98 ms 6388 KB Output is correct
26 Correct 96 ms 6380 KB Output is correct
27 Correct 121 ms 6232 KB Output is correct
28 Correct 123 ms 6232 KB Output is correct
29 Correct 119 ms 6236 KB Output is correct
30 Correct 114 ms 6748 KB Output is correct
31 Correct 7 ms 604 KB Output is correct
32 Correct 9 ms 524 KB Output is correct
33 Execution timed out 1064 ms 4956 KB Time limit exceeded
34 Halted 0 ms 0 KB -