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Submission #834517

# Submission time Handle Problem Language Result Execution time Memory
834517 2023-08-22T15:10:05 Z _martynas Aesthetic (NOI20_aesthetic) C++11
51 / 100
 754 ms 77792 KB 
#include <bits/stdc++.h>
    
using namespace std;
    
using ll = long long;
    
#warning change mxn
const int mxn = 3e5+5;
const ll inf = 1e16;
    
struct Edge {
    int to, id;
};
    
int n, m;
int A[mxn], B[mxn];
vector<Edge> adj[mxn];
ll W[mxn];
vector<Edge> adj2[mxn];
bool isbridge[mxn], visited[mxn];
vector<ll> from1, fromn;
    
vector<ll> get_min_dist(int start) {
    vector<long long> dist(n+1, inf);
    priority_queue<pair<ll, int>> pq;
    dist[start] = 0;
    pq.push({-dist[start], start});;
    while(!pq.empty()) {
        ll d = -pq.top().first;
        int a = pq.top().second;
        pq.pop();
        if(dist[a] != d) continue;
        for(auto e : adj[a]) if(dist[e.to] > d+W[e.id]) {
            dist[e.to] = d+W[e.id];
            pq.push({-dist[e.to], e.to});
        }
    }
    return dist;
}
    
    
int tim = 0;
int disc[mxn], low[mxn];
bool onpathton[mxn];
void bridge_det(int u, int par) {
    visited[u] = true;
    if(u == n) onpathton[u] = true;
    low[u] = disc[u] = tim++;
    for(auto e : adj2[u]) if(e.to != par) {
        if(!visited[e.to]) {
            bridge_det(e.to, u);
            if(low[e.to] > disc[u] && onpathton[e.to]) {
                isbridge[e.id] = true;
            }
        }
        onpathton[u] = onpathton[u] || onpathton[e.to];
        low[u] = min(low[u], low[e.to]);
    }
}
    
int main(int argc, char const *argv[]) {
    cin >> n >> m;
    for(int i = 1; i <= m; i++) {
        cin >> A[i] >> B[i] >> W[i];
        adj[A[i]].push_back({B[i], i});
        adj[B[i]].push_back({A[i], i});
    }
    from1 = get_min_dist(1);
    fromn = get_min_dist(n);
    ll mxw = W[m];
    vector<ll> ans(m+1);
    for(int i = m-1; i >= 1; i--) {
        ll nw = W[i]+mxw;
        ll mndist = inf;
        mndist = min(mndist, from1[A[i]]+fromn[B[i]]+nw);
        mndist = min(mndist, from1[B[i]]+fromn[A[i]]+nw);
        ans[i] = mndist;
        mxw = max(mxw, W[i]);
    }
    // build new graph where every path is min
    for(int i = 1; i <= m; i++) {
        if(from1[A[i]]+fromn[B[i]]+W[i] == from1[n] || from1[B[i]]+fromn[A[i]]+W[i] == from1[n]) {
            adj2[A[i]].push_back({B[i], i});
            adj2[B[i]].push_back({A[i], i});
        }
    }
    // printf("new graph\n");
    // for(int i = 1; i <= n; i++) {
    //     printf("%d: ", i);
    //     for(auto e : adj2[i]) {
    //         printf("%d (%d), ", e.to, e.id);
    //     }
    //     printf("\n");
    // }
    fill(low, low+n+1, mxn);
    bridge_det(1, -1);
    // printf("bridge: ");
    // for(int i = m; i >= 1; i--) if(isbridge[i]) printf("%d ", i);
    // printf("\n");
    vector<int> cnt_to_id(m+1);
    fill(visited, visited+n+1, false);
    queue<int> q;
    visited[1] = true; q.push(1);
    int c = 0;
    while(!q.empty()) {
        int u = q.front(); q.pop();
        for(auto e : adj2[u]) if(!visited[e.to]) {
            visited[e.to] = true;
            c += isbridge[e.id];
            cnt_to_id[c] = e.id;
            q.push(e.to);
        }
    }
    vector<long long> dist(n+1, inf);
    vector<int> cnt(n+1);
    priority_queue<pair<pair<ll, int>, int>> pq;
    vector<Edge> used_edge; vector<int> from;
    dist[1] = 0, cnt[1] = 0;
    pq.push({{-dist[1], 1}, -1});
    vector<vector<ll>> ins(m+1), del(m+1);
    while(!pq.empty()) {
        ll d = -pq.top().first.first;
        int a = pq.top().first.second;
        int edgeidx = pq.top().second;
        pq.pop();
        if(edgeidx != -1) {
            // cerr << from[edgeidx] << " -> " << a << "\n";
            // cerr << cnt[from[edgeidx]]+isbridge[used_edge[edgeidx].id] << "; " << cnt[a] << "\n";
            if(cnt[used_edge[edgeidx].to] > cnt[from[edgeidx]]+isbridge[used_edge[edgeidx].id]) {
                int l = cnt[from[edgeidx]]+isbridge[used_edge[edgeidx].id]+1, r = cnt[a];
                ll val = from1[from[edgeidx]]+W[used_edge[edgeidx].id]+fromn[a];
                // for(int i = l; i <= r; i++) {
                //     // cerr << "modify " << cnt_to_id[i] << "\n";
                //     ans[cnt_to_id[i]] = min(ans[cnt_to_id[i]], val);
                // }
                // cerr << l << "; " << r << ": " << val << "\n";
                ins[l].push_back(val);
                del[r].push_back(val);
            }
        }
        if(dist[a] != d) continue;
        // cerr << a << " " << d << "\n";
        for(auto e : adj[a]) {
            if(dist[e.to] > d+W[e.id]) {
                cnt[e.to] = cnt[a]+isbridge[e.id];
                dist[e.to] = d+W[e.id];
                pq.push({{-dist[e.to], e.to}, used_edge.size()});
                used_edge.push_back(e); from.push_back(a);
                // cerr << "add " << from.back() << " " << used_edge.back().to << "\n";
            }
            else {
                // cerr << a << " -> " << e.to << "\n";
                // cerr << cnt[a]+isbridge[e.id] << "; " << cnt[e.to] << "\n";
                if(cnt[e.to] > cnt[a]+isbridge[e.id]) {
                    int l = cnt[a]+isbridge[e.id]+1, r = cnt[e.to];
                    ll val = from1[a]+W[e.id]+fromn[e.to];
                    // for(int i = l; i <= r; i++)  {
                    //     // cerr << i << ": " << cnt_to_id[i] << "?\n";
                    //     ans[cnt_to_id[i]] = min(ans[cnt_to_id[i]], val);
                    // }
                    // cerr << l << "; " << r << ": " << val << "\n";
                    ins[l].push_back(val);
                    del[r].push_back(val);
                }
            }
        }
    }
    multiset<ll> available;
    for(int i = 0; i <= m; i++) {
        for(ll x : ins[i]) available.insert(x);
        if(cnt_to_id[i] != 0 && !available.empty()) {
            // cerr << cnt_to_id[i] << " <- " << (*available.begin()) << "\n";
            ans[cnt_to_id[i]] = min(ans[cnt_to_id[i]], *available.begin());
        }
        for(ll x : del[i]) available.erase(available.find(x));
    }
    ll answer = 0;
    for(int i = 1; i < m; i++) {
        // cerr << ans[i] << " ";
        answer = max(answer, isbridge[i] ? ans[i] : from1[n]);
    }
    // cerr << "\n";
    cout << answer << "\n";
    return 0;
}

Compilation message

Aesthetic.cpp:7:2: warning: #warning change mxn [-Wcpp]
    7 | #warning change mxn
      |  ^~~~~~~

Subtask #1
5.0 / 5.0

# Verdict Execution time Memory Grader output
1 Correct 6 ms 14420 KB Output is correct
2 Correct 6 ms 14400 KB Output is correct
3 Correct 7 ms 14400 KB Output is correct
4 Correct 8 ms 14420 KB Output is correct
5 Correct 6 ms 14416 KB Output is correct
6 Correct 7 ms 14372 KB Output is correct
7 Correct 8 ms 14420 KB Output is correct
8 Correct 7 ms 14416 KB Output is correct

Subtask #2
8.0 / 8.0

# Verdict Execution time Memory Grader output
1 Correct 6 ms 14420 KB Output is correct
2 Correct 6 ms 14400 KB Output is correct
3 Correct 7 ms 14400 KB Output is correct
4 Correct 8 ms 14420 KB Output is correct
5 Correct 6 ms 14416 KB Output is correct
6 Correct 7 ms 14372 KB Output is correct
7 Correct 8 ms 14420 KB Output is correct
8 Correct 7 ms 14416 KB Output is correct
9 Correct 9 ms 14804 KB Output is correct
10 Correct 9 ms 14676 KB Output is correct
11 Correct 10 ms 14680 KB Output is correct
12 Correct 9 ms 14684 KB Output is correct
13 Correct 9 ms 14732 KB Output is correct
14 Correct 9 ms 14728 KB Output is correct
15 Correct 9 ms 14680 KB Output is correct
16 Correct 9 ms 14680 KB Output is correct

Subtask #3
7.0 / 7.0

# Verdict Execution time Memory Grader output
1 Correct 729 ms 65456 KB Output is correct
2 Correct 753 ms 65568 KB Output is correct
3 Correct 693 ms 65204 KB Output is correct
4 Correct 697 ms 65176 KB Output is correct
5 Correct 681 ms 65464 KB Output is correct
6 Correct 726 ms 66368 KB Output is correct
7 Correct 751 ms 66020 KB Output is correct
8 Correct 754 ms 66436 KB Output is correct

Subtask #4
15.0 / 15.0

# Verdict Execution time Memory Grader output
1 Correct 737 ms 66460 KB Output is correct
2 Correct 646 ms 65796 KB Output is correct
3 Correct 660 ms 65252 KB Output is correct
4 Correct 638 ms 65456 KB Output is correct
5 Correct 613 ms 65472 KB Output is correct
6 Correct 596 ms 65476 KB Output is correct
7 Correct 606 ms 65604 KB Output is correct
8 Correct 701 ms 65976 KB Output is correct

Subtask #5
16.0 / 16.0

# Verdict Execution time Memory Grader output
1 Correct 463 ms 59320 KB Output is correct
2 Correct 337 ms 60296 KB Output is correct
3 Correct 387 ms 67252 KB Output is correct
4 Correct 352 ms 67292 KB Output is correct
5 Correct 422 ms 67128 KB Output is correct
6 Correct 385 ms 67292 KB Output is correct
7 Correct 354 ms 67444 KB Output is correct
8 Correct 354 ms 67392 KB Output is correct
9 Correct 356 ms 67256 KB Output is correct
10 Correct 378 ms 67736 KB Output is correct
11 Correct 359 ms 67388 KB Output is correct
12 Correct 474 ms 60844 KB Output is correct
13 Correct 378 ms 67412 KB Output is correct
14 Correct 255 ms 77792 KB Output is correct
15 Correct 240 ms 75284 KB Output is correct
16 Correct 509 ms 58844 KB Output is correct
17 Correct 536 ms 59676 KB Output is correct
18 Correct 551 ms 58428 KB Output is correct
19 Correct 300 ms 60096 KB Output is correct
20 Correct 317 ms 60260 KB Output is correct
21 Correct 301 ms 60148 KB Output is correct
22 Correct 304 ms 60128 KB Output is correct

Subtask #6
0 / 22.0

# Verdict Execution time Memory Grader output
1 Correct 463 ms 59320 KB Output is correct
2 Correct 337 ms 60296 KB Output is correct
3 Correct 387 ms 67252 KB Output is correct
4 Correct 352 ms 67292 KB Output is correct
5 Correct 422 ms 67128 KB Output is correct
6 Correct 385 ms 67292 KB Output is correct
7 Correct 354 ms 67444 KB Output is correct
8 Correct 354 ms 67392 KB Output is correct
9 Correct 356 ms 67256 KB Output is correct
10 Correct 378 ms 67736 KB Output is correct
11 Correct 359 ms 67388 KB Output is correct
12 Correct 474 ms 60844 KB Output is correct
13 Correct 378 ms 67412 KB Output is correct
14 Correct 255 ms 77792 KB Output is correct
15 Correct 240 ms 75284 KB Output is correct
16 Correct 509 ms 58844 KB Output is correct
17 Correct 536 ms 59676 KB Output is correct
18 Correct 551 ms 58428 KB Output is correct
19 Correct 300 ms 60096 KB Output is correct
20 Correct 317 ms 60260 KB Output is correct
21 Correct 301 ms 60148 KB Output is correct
22 Correct 304 ms 60128 KB Output is correct
23 Correct 641 ms 62536 KB Output is correct
24 Correct 349 ms 62696 KB Output is correct
25 Correct 329 ms 51036 KB Output is correct
26 Incorrect 348 ms 54480 KB Output isn't correct
27 Halted 0 ms 0 KB -

Subtask #7
0 / 27.0

# Verdict Execution time Memory Grader output
1 Correct 6 ms 14420 KB Output is correct
2 Correct 6 ms 14400 KB Output is correct
3 Correct 7 ms 14400 KB Output is correct
4 Correct 8 ms 14420 KB Output is correct
5 Correct 6 ms 14416 KB Output is correct
6 Correct 7 ms 14372 KB Output is correct
7 Correct 8 ms 14420 KB Output is correct
8 Correct 7 ms 14416 KB Output is correct
9 Correct 9 ms 14804 KB Output is correct
10 Correct 9 ms 14676 KB Output is correct
11 Correct 10 ms 14680 KB Output is correct
12 Correct 9 ms 14684 KB Output is correct
13 Correct 9 ms 14732 KB Output is correct
14 Correct 9 ms 14728 KB Output is correct
15 Correct 9 ms 14680 KB Output is correct
16 Correct 9 ms 14680 KB Output is correct
17 Correct 729 ms 65456 KB Output is correct
18 Correct 753 ms 65568 KB Output is correct
19 Correct 693 ms 65204 KB Output is correct
20 Correct 697 ms 65176 KB Output is correct
21 Correct 681 ms 65464 KB Output is correct
22 Correct 726 ms 66368 KB Output is correct
23 Correct 751 ms 66020 KB Output is correct
24 Correct 754 ms 66436 KB Output is correct
25 Correct 737 ms 66460 KB Output is correct
26 Correct 646 ms 65796 KB Output is correct
27 Correct 660 ms 65252 KB Output is correct
28 Correct 638 ms 65456 KB Output is correct
29 Correct 613 ms 65472 KB Output is correct
30 Correct 596 ms 65476 KB Output is correct
31 Correct 606 ms 65604 KB Output is correct
32 Correct 701 ms 65976 KB Output is correct
33 Correct 463 ms 59320 KB Output is correct
34 Correct 337 ms 60296 KB Output is correct
35 Correct 387 ms 67252 KB Output is correct
36 Correct 352 ms 67292 KB Output is correct
37 Correct 422 ms 67128 KB Output is correct
38 Correct 385 ms 67292 KB Output is correct
39 Correct 354 ms 67444 KB Output is correct
40 Correct 354 ms 67392 KB Output is correct
41 Correct 356 ms 67256 KB Output is correct
42 Correct 378 ms 67736 KB Output is correct
43 Correct 359 ms 67388 KB Output is correct
44 Correct 474 ms 60844 KB Output is correct
45 Correct 378 ms 67412 KB Output is correct
46 Correct 255 ms 77792 KB Output is correct
47 Correct 240 ms 75284 KB Output is correct
48 Correct 509 ms 58844 KB Output is correct
49 Correct 536 ms 59676 KB Output is correct
50 Correct 551 ms 58428 KB Output is correct
51 Correct 300 ms 60096 KB Output is correct
52 Correct 317 ms 60260 KB Output is correct
53 Correct 301 ms 60148 KB Output is correct
54 Correct 304 ms 60128 KB Output is correct
55 Correct 641 ms 62536 KB Output is correct
56 Correct 349 ms 62696 KB Output is correct
57 Correct 329 ms 51036 KB Output is correct
58 Incorrect 348 ms 54480 KB Output isn't correct
59 Halted 0 ms 0 KB -