oj.uz

Submission #922408

# Submission time Handle Problem Language Result Execution time Memory
922408 2024-02-05T13:31:55 Z GrindMachine Olympic Bus (JOI20_ho_t4) C++17
16 / 100
 1000 ms 5980 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;
            }
        }
    };

    if(dis1[n] != inf2){
        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);
    if(disn[1] != inf2){
        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:235:17: note: in expansion of macro 'debug'
  235 |                 debug(i);
      |                 ^~~~~
ho_t4.cpp:46:18: warning: statement has no effect [-Wunused-value]
   46 | #define debug(x) 42
      |                  ^~
ho_t4.cpp:236:17: note: in expansion of macro 'debug'
  236 |                 debug(sp_1_n);
      |                 ^~~~~
ho_t4.cpp:46:18: warning: statement has no effect [-Wunused-value]
   46 | #define debug(x) 42
      |                  ^~
ho_t4.cpp:237:17: note: in expansion of macro 'debug'
  237 |                 debug(sp_n_1);
      |                 ^~~~~
ho_t4.cpp:46:18: warning: statement has no effect [-Wunused-value]
   46 | #define debug(x) 42
      |                  ^~
ho_t4.cpp:238:17: note: in expansion of macro 'debug'
  238 |                 debug(disn[1]);
      |                 ^~~~~

Subtask #1
5.0 / 5.0

# Verdict Execution time Memory Grader output
1 Correct 7 ms 604 KB Output is correct
2 Correct 1 ms 348 KB Output is correct
3 Correct 56 ms 604 KB Output is correct
4 Correct 58 ms 600 KB Output is correct
5 Correct 3 ms 604 KB Output is correct
6 Correct 1 ms 348 KB Output is correct
7 Correct 0 ms 348 KB Output is correct
8 Correct 0 ms 348 KB Output is correct
9 Correct 1 ms 348 KB Output is correct
10 Correct 46 ms 604 KB Output is correct
11 Correct 58 ms 604 KB Output is correct
12 Correct 53 ms 600 KB Output is correct
13 Correct 1 ms 604 KB Output is correct
14 Correct 35 ms 604 KB Output is correct
15 Correct 33 ms 760 KB Output is correct
16 Correct 33 ms 600 KB Output is correct

Subtask #2
11.0 / 11.0

# Verdict Execution time Memory Grader output
1 Correct 141 ms 5464 KB Output is correct
2 Correct 141 ms 5464 KB Output is correct
3 Correct 153 ms 5208 KB Output is correct
4 Correct 7 ms 600 KB Output is correct
5 Correct 3 ms 344 KB Output is correct
6 Correct 1 ms 348 KB Output is correct
7 Correct 1 ms 344 KB Output is correct
8 Correct 0 ms 468 KB Output is correct
9 Correct 18 ms 5468 KB Output is correct
10 Correct 18 ms 5560 KB Output is correct
11 Correct 81 ms 5468 KB Output is correct
12 Correct 81 ms 5472 KB Output is correct
13 Correct 80 ms 5468 KB Output is correct
14 Correct 80 ms 5980 KB Output is correct

Subtask #3
0 / 21.0

# Verdict Execution time Memory Grader output
1 Correct 6 ms 604 KB Output is correct
2 Correct 8 ms 524 KB Output is correct
3 Execution timed out 1075 ms 4892 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 604 KB Output is correct
2 Correct 1 ms 348 KB Output is correct
3 Correct 56 ms 604 KB Output is correct
4 Correct 58 ms 600 KB Output is correct
5 Correct 3 ms 604 KB Output is correct
6 Correct 1 ms 348 KB Output is correct
7 Correct 0 ms 348 KB Output is correct
8 Correct 0 ms 348 KB Output is correct
9 Correct 1 ms 348 KB Output is correct
10 Correct 46 ms 604 KB Output is correct
11 Correct 58 ms 604 KB Output is correct
12 Correct 53 ms 600 KB Output is correct
13 Correct 1 ms 604 KB Output is correct
14 Correct 35 ms 604 KB Output is correct
15 Correct 33 ms 760 KB Output is correct
16 Correct 33 ms 600 KB Output is correct
17 Correct 141 ms 5464 KB Output is correct
18 Correct 141 ms 5464 KB Output is correct
19 Correct 153 ms 5208 KB Output is correct
20 Correct 7 ms 600 KB Output is correct
21 Correct 3 ms 344 KB Output is correct
22 Correct 1 ms 348 KB Output is correct
23 Correct 1 ms 344 KB Output is correct
24 Correct 0 ms 468 KB Output is correct
25 Correct 18 ms 5468 KB Output is correct
26 Correct 18 ms 5560 KB Output is correct
27 Correct 81 ms 5468 KB Output is correct
28 Correct 81 ms 5472 KB Output is correct
29 Correct 80 ms 5468 KB Output is correct
30 Correct 80 ms 5980 KB Output is correct
31 Correct 6 ms 604 KB Output is correct
32 Correct 8 ms 524 KB Output is correct
33 Execution timed out 1075 ms 4892 KB Time limit exceeded
34 Halted 0 ms 0 KB -