oj.uz

Submission #922395

# Submission time Handle Problem Language Result Execution time Memory
922395 2024-02-05T13:19:07 Z GrindMachine Olympic Bus (JOI20_ho_t4) C++17
5 / 100
 1000 ms 6200 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(1,-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);

    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:229:17: note: in expansion of macro 'debug'
  229 |                 debug(i);
      |                 ^~~~~
ho_t4.cpp:46:18: warning: statement has no effect [-Wunused-value]
   46 | #define debug(x) 42
      |                  ^~
ho_t4.cpp:230:17: note: in expansion of macro 'debug'
  230 |                 debug(sp_1_n);
      |                 ^~~~~
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(sp_n_1);
      |                 ^~~~~
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(disn[1]);
      |                 ^~~~~

Subtask #1
5.0 / 5.0

# Verdict Execution time Memory Grader output
1 Correct 7 ms 600 KB Output is correct
2 Correct 21 ms 348 KB Output is correct
3 Correct 174 ms 608 KB Output is correct
4 Correct 177 ms 616 KB Output is correct
5 Correct 13 ms 604 KB Output is correct
6 Correct 2 ms 348 KB Output is correct
7 Correct 0 ms 600 KB Output is correct
8 Correct 0 ms 348 KB Output is correct
9 Correct 2 ms 348 KB Output is correct
10 Correct 178 ms 612 KB Output is correct
11 Correct 185 ms 604 KB Output is correct
12 Correct 178 ms 612 KB Output is correct
13 Correct 153 ms 604 KB Output is correct
14 Correct 168 ms 848 KB Output is correct
15 Correct 155 ms 604 KB Output is correct
16 Correct 154 ms 612 KB Output is correct

Subtask #2
0 / 11.0

# Verdict Execution time Memory Grader output
1 Execution timed out 1034 ms 6200 KB Time limit exceeded
2 Halted 0 ms 0 KB -

Subtask #3
0 / 21.0

# Verdict Execution time Memory Grader output
1 Correct 10 ms 756 KB Output is correct
2 Correct 25 ms 348 KB Output is correct
3 Execution timed out 1073 ms 5468 KB Time limit exceeded
4 Halted 0 ms 0 KB -

Subtask #4
0 / 63.0

# Verdict Execution time Memory Grader output
1 Correct 7 ms 600 KB Output is correct
2 Correct 21 ms 348 KB Output is correct
3 Correct 174 ms 608 KB Output is correct
4 Correct 177 ms 616 KB Output is correct
5 Correct 13 ms 604 KB Output is correct
6 Correct 2 ms 348 KB Output is correct
7 Correct 0 ms 600 KB Output is correct
8 Correct 0 ms 348 KB Output is correct
9 Correct 2 ms 348 KB Output is correct
10 Correct 178 ms 612 KB Output is correct
11 Correct 185 ms 604 KB Output is correct
12 Correct 178 ms 612 KB Output is correct
13 Correct 153 ms 604 KB Output is correct
14 Correct 168 ms 848 KB Output is correct
15 Correct 155 ms 604 KB Output is correct
16 Correct 154 ms 612 KB Output is correct
17 Execution timed out 1034 ms 6200 KB Time limit exceeded
18 Halted 0 ms 0 KB -