oj.uz

Submission #255303

# Submission time Handle Problem Language Result Execution time Memory
255303 2020-07-31T17:14:51 Z model_code Aesthetic (NOI20_aesthetic) C++17
100 / 100
 732 ms 60952 KB 
#include <bits/stdc++.h>
using namespace std;
constexpr int MAXN=300'000;
constexpr int MAXM=300'000;
vector<pair<int,int>>adj[MAXN]; // (target, edgeindex)
vector<pair<int,int>> backadj[MAXN]; // target, edgeindex
int weight[MAXM];
int delta[MAXM];
int direction[MAXM]; // set to the index of the to-direction
long long dist[MAXN];
int liveliness[MAXN];
bool visited[MAXN];
int waiting[MAXN];
vector<int> bridges;
bool isbridge[MAXM];
//long long bridgescore[MAXM];
vector<pair<pair<int,int>, long long>> ranges; // <[begin, end), score>
struct rangepqcmp{
    bool operator()(const pair<long long,int>& a, const pair<long long,int>& b) { return a.first > b.first; }
};
priority_queue<pair<long long,int>, vector<pair<long long,int>>, rangepqcmp> rangepq; // <score, end>
int tracks;
int arc[MAXN];
void dfs1(int index){
    visited[index]=true;
    for(const pair<int,int>& x : backadj[index]){
        liveliness[x.first]++;
        if(!visited[x.first])dfs1(x.first);
    }
}
void dfs2(int index){
    if(waiting[index]+1!=liveliness[index]){
        waiting[index]++;
        return;
    }
    tracks-=waiting[index];
    if(backadj[index].empty())return; // reached the source
    if(tracks==1&&backadj[index].size()==1){
        const int bridge=backadj[index][0].second;
        bridges.push_back(bridge);
        isbridge[bridge]=true;
    }
    tracks+=static_cast<int>(backadj[index].size())-1;
    for(const pair<int,int>& x : backadj[index]){
        dfs2(x.first);
    }
}
int main(){
    ios_base::sync_with_stdio(false);
    int n,m;
    cin>>n>>m;
    for(int i=0;i<m;++i){
        int a,b,w;
        cin>>a>>b>>w;
        weight[i]=w;
        --a;--b;
        adj[a].emplace_back(b,i);
        adj[b].emplace_back(a,i);
    }
    {
        int best=numeric_limits<int>::min();
        for(int i=m-1;i>=0;--i){
            delta[i]=best;
            best=max(best, weight[i]);
        }
    }
    fill(dist,dist+n,numeric_limits<long long>::max());
    fill(direction,direction+m,-1);
    {
        struct elem{
            int source;
            int target;
            long long distance;
            int edgeindex;
        };
        struct cmp{
            bool operator()(const elem& a, const elem& b) const noexcept{
                return a.distance>b.distance;
            }
        };
        priority_queue<elem,vector<elem>,cmp> pq;
        pq.push({-1,0,0,-1});
        while(!pq.empty()){
            elem tmp=pq.top();
            pq.pop();
            if(dist[tmp.target]!=numeric_limits<long long>::max()){
                if(dist[tmp.target]==tmp.distance){
                    backadj[tmp.target].emplace_back(tmp.source,tmp.edgeindex);
                }
                continue;
            }
            dist[tmp.target]=tmp.distance;
            backadj[tmp.target].emplace_back(tmp.source,tmp.edgeindex);
            for(const pair<int,int>& pr: adj[tmp.target]){
                if(direction[pr.second]==-1){
                    direction[pr.second]=pr.first;
                    pq.push({tmp.target,pr.first,tmp.distance+weight[pr.second],pr.second});
                }
            }
        }
    }
    backadj[0].clear();
    /*for(int i=0;i<n;++i){
        cout<<i<<": ";
        for(const auto& pr:backadj[i]){
            cout<<pr.first<<' '<<pr.second<<"   ";
        }
        cout<<endl;
    }*/
    dfs1(n-1);
    /*cout<<"Liveliness:";
    for(int i=0;i<n;++i){
        cout<<' '<<liveliness[i];
    }
    cout<<endl;*/
    fill(visited,visited+n,false);
    tracks=1;
    liveliness[n-1]=1;
    dfs2(n-1);
    /*cout<<"Bridges:";
    for(auto x:bridges){
        cout<<' '<<x;
    }
    cout<<endl;*/
    if(bridges.empty()){
        cout<<dist[n-1]<<'\n';
        return 0;
    }
    /*for(int x : bridges){
        bridgescore[x]=dist[n-1]+delta[x];
    }*/
    fill(arc,arc+n,numeric_limits<int>::max());
    {
        struct elem{
            int target;
            long long distance;
            int arc;
        };
        struct cmp{
            bool operator()(const elem& a, const elem& b) const noexcept{
                return a.distance>b.distance;
            }
        };
        priority_queue<elem,vector<elem>,cmp> pq;
        pq.push({n-1,0,0});
        while(!pq.empty()){
            elem tmp=pq.top();
            pq.pop();
            if(arc[tmp.target]!=numeric_limits<int>::max()){
                if(arc[tmp.target]>tmp.arc){
                    //cout<<tmp.target<<' '<<tmp.arc<<' '<<tmp.distance<<' '<<dist[tmp.target]<<endl;
                    ranges.push_back({{tmp.arc, arc[tmp.target]}, tmp.distance+dist[tmp.target]});
                    /*for(int i=tmp.arc;i!=arc[tmp.target];++i){
                        bridgescore[bridges[i]]=min(bridgescore[bridges[i]],tmp.distance+dist[tmp.target]);
                    }*/
                }
                continue;
            }
            arc[tmp.target]=tmp.arc;
            for(const pair<int,int>& pr:adj[tmp.target]){
                if(isbridge[pr.second]){
                    pq.push({pr.first,tmp.distance+weight[pr.second],tmp.arc+1});
                }else {
                    pq.push({pr.first,tmp.distance+weight[pr.second],tmp.arc});
                }
            }
        }
    }
    sort(ranges.begin(), ranges.end(), [](const pair<pair<int,int>, long long>& a, const pair<pair<int,int>, long long>& b) {
        return a.first.first < b.first.first;
    });
    long long ans=dist[n-1];
    auto range_it=ranges.begin();
    for(int i=0;i<static_cast<int>(bridges.size());++i){
        long long bmin=dist[n-1]+delta[bridges[i]];
        while(!rangepq.empty()&&rangepq.top().second<=i)rangepq.pop();
        while(range_it!=ranges.end()&&range_it->first.first==i){
            rangepq.push({range_it->second,range_it->first.second});
            ++range_it;
        }
        if(!rangepq.empty())bmin=min(bmin,rangepq.top().first);
        ans=max(ans,bmin);
    }
    /*for(const int x:bridges){
        ans=max(ans,bridgescore[x]);
    }*/
    cout<<ans<<'\n';
}

Subtask #1
5.0 / 5.0

# Verdict Execution time Memory Grader output
1 Correct 13 ms 14464 KB Output is correct
2 Correct 9 ms 14464 KB Output is correct
3 Correct 11 ms 14464 KB Output is correct
4 Correct 11 ms 14464 KB Output is correct
5 Correct 10 ms 14464 KB Output is correct
6 Correct 10 ms 14464 KB Output is correct
7 Correct 11 ms 14464 KB Output is correct
8 Correct 9 ms 14464 KB Output is correct

Subtask #2
8.0 / 8.0

# Verdict Execution time Memory Grader output
1 Correct 13 ms 14464 KB Output is correct
2 Correct 9 ms 14464 KB Output is correct
3 Correct 11 ms 14464 KB Output is correct
4 Correct 11 ms 14464 KB Output is correct
5 Correct 10 ms 14464 KB Output is correct
6 Correct 10 ms 14464 KB Output is correct
7 Correct 11 ms 14464 KB Output is correct
8 Correct 9 ms 14464 KB Output is correct
9 Correct 10 ms 14720 KB Output is correct
10 Correct 12 ms 14720 KB Output is correct
11 Correct 11 ms 14720 KB Output is correct
12 Correct 12 ms 14720 KB Output is correct
13 Correct 12 ms 14592 KB Output is correct
14 Correct 12 ms 14592 KB Output is correct
15 Correct 11 ms 14592 KB Output is correct
16 Correct 11 ms 14720 KB Output is correct

Subtask #3
7.0 / 7.0

# Verdict Execution time Memory Grader output
1 Correct 620 ms 42876 KB Output is correct
2 Correct 624 ms 42784 KB Output is correct
3 Correct 588 ms 42608 KB Output is correct
4 Correct 580 ms 42744 KB Output is correct
5 Correct 588 ms 42908 KB Output is correct
6 Correct 667 ms 43512 KB Output is correct
7 Correct 642 ms 43128 KB Output is correct
8 Correct 617 ms 43384 KB Output is correct

Subtask #4
15.0 / 15.0

# Verdict Execution time Memory Grader output
1 Correct 593 ms 43384 KB Output is correct
2 Correct 593 ms 43128 KB Output is correct
3 Correct 596 ms 42488 KB Output is correct
4 Correct 602 ms 42488 KB Output is correct
5 Correct 595 ms 42744 KB Output is correct
6 Correct 586 ms 42744 KB Output is correct
7 Correct 597 ms 42924 KB Output is correct
8 Correct 625 ms 43208 KB Output is correct

Subtask #5
16.0 / 16.0

# Verdict Execution time Memory Grader output
1 Correct 528 ms 46248 KB Output is correct
2 Correct 258 ms 40844 KB Output is correct
3 Correct 266 ms 32120 KB Output is correct
4 Correct 279 ms 32188 KB Output is correct
5 Correct 270 ms 32252 KB Output is correct
6 Correct 298 ms 32248 KB Output is correct
7 Correct 316 ms 32212 KB Output is correct
8 Correct 296 ms 32156 KB Output is correct
9 Correct 266 ms 32248 KB Output is correct
10 Correct 267 ms 32376 KB Output is correct
11 Correct 278 ms 32248 KB Output is correct
12 Correct 518 ms 46592 KB Output is correct
13 Correct 287 ms 32248 KB Output is correct
14 Correct 213 ms 44588 KB Output is correct
15 Correct 216 ms 46952 KB Output is correct
16 Correct 514 ms 46728 KB Output is correct
17 Correct 504 ms 44900 KB Output is correct
18 Correct 530 ms 46352 KB Output is correct
19 Correct 270 ms 40952 KB Output is correct
20 Correct 273 ms 40952 KB Output is correct
21 Correct 259 ms 41016 KB Output is correct
22 Correct 268 ms 40988 KB Output is correct

Subtask #6
22.0 / 22.0

# Verdict Execution time Memory Grader output
1 Correct 528 ms 46248 KB Output is correct
2 Correct 258 ms 40844 KB Output is correct
3 Correct 266 ms 32120 KB Output is correct
4 Correct 279 ms 32188 KB Output is correct
5 Correct 270 ms 32252 KB Output is correct
6 Correct 298 ms 32248 KB Output is correct
7 Correct 316 ms 32212 KB Output is correct
8 Correct 296 ms 32156 KB Output is correct
9 Correct 266 ms 32248 KB Output is correct
10 Correct 267 ms 32376 KB Output is correct
11 Correct 278 ms 32248 KB Output is correct
12 Correct 518 ms 46592 KB Output is correct
13 Correct 287 ms 32248 KB Output is correct
14 Correct 213 ms 44588 KB Output is correct
15 Correct 216 ms 46952 KB Output is correct
16 Correct 514 ms 46728 KB Output is correct
17 Correct 504 ms 44900 KB Output is correct
18 Correct 530 ms 46352 KB Output is correct
19 Correct 270 ms 40952 KB Output is correct
20 Correct 273 ms 40952 KB Output is correct
21 Correct 259 ms 41016 KB Output is correct
22 Correct 268 ms 40988 KB Output is correct
23 Correct 641 ms 46596 KB Output is correct
24 Correct 309 ms 41236 KB Output is correct
25 Correct 273 ms 30456 KB Output is correct
26 Correct 375 ms 36036 KB Output is correct
27 Correct 367 ms 35272 KB Output is correct
28 Correct 359 ms 32204 KB Output is correct
29 Correct 387 ms 36292 KB Output is correct
30 Correct 380 ms 35656 KB Output is correct
31 Correct 385 ms 35592 KB Output is correct
32 Correct 361 ms 35404 KB Output is correct
33 Correct 374 ms 32868 KB Output is correct
34 Correct 619 ms 46364 KB Output is correct
35 Correct 348 ms 33736 KB Output is correct
36 Correct 248 ms 60820 KB Output is correct
37 Correct 271 ms 60952 KB Output is correct
38 Correct 587 ms 46268 KB Output is correct
39 Correct 557 ms 46044 KB Output is correct
40 Correct 581 ms 46572 KB Output is correct
41 Correct 298 ms 41236 KB Output is correct
42 Correct 296 ms 41196 KB Output is correct
43 Correct 299 ms 41244 KB Output is correct
44 Correct 298 ms 41332 KB Output is correct

Subtask #7
27.0 / 27.0

# Verdict Execution time Memory Grader output
1 Correct 13 ms 14464 KB Output is correct
2 Correct 9 ms 14464 KB Output is correct
3 Correct 11 ms 14464 KB Output is correct
4 Correct 11 ms 14464 KB Output is correct
5 Correct 10 ms 14464 KB Output is correct
6 Correct 10 ms 14464 KB Output is correct
7 Correct 11 ms 14464 KB Output is correct
8 Correct 9 ms 14464 KB Output is correct
9 Correct 10 ms 14720 KB Output is correct
10 Correct 12 ms 14720 KB Output is correct
11 Correct 11 ms 14720 KB Output is correct
12 Correct 12 ms 14720 KB Output is correct
13 Correct 12 ms 14592 KB Output is correct
14 Correct 12 ms 14592 KB Output is correct
15 Correct 11 ms 14592 KB Output is correct
16 Correct 11 ms 14720 KB Output is correct
17 Correct 620 ms 42876 KB Output is correct
18 Correct 624 ms 42784 KB Output is correct
19 Correct 588 ms 42608 KB Output is correct
20 Correct 580 ms 42744 KB Output is correct
21 Correct 588 ms 42908 KB Output is correct
22 Correct 667 ms 43512 KB Output is correct
23 Correct 642 ms 43128 KB Output is correct
24 Correct 617 ms 43384 KB Output is correct
25 Correct 593 ms 43384 KB Output is correct
26 Correct 593 ms 43128 KB Output is correct
27 Correct 596 ms 42488 KB Output is correct
28 Correct 602 ms 42488 KB Output is correct
29 Correct 595 ms 42744 KB Output is correct
30 Correct 586 ms 42744 KB Output is correct
31 Correct 597 ms 42924 KB Output is correct
32 Correct 625 ms 43208 KB Output is correct
33 Correct 528 ms 46248 KB Output is correct
34 Correct 258 ms 40844 KB Output is correct
35 Correct 266 ms 32120 KB Output is correct
36 Correct 279 ms 32188 KB Output is correct
37 Correct 270 ms 32252 KB Output is correct
38 Correct 298 ms 32248 KB Output is correct
39 Correct 316 ms 32212 KB Output is correct
40 Correct 296 ms 32156 KB Output is correct
41 Correct 266 ms 32248 KB Output is correct
42 Correct 267 ms 32376 KB Output is correct
43 Correct 278 ms 32248 KB Output is correct
44 Correct 518 ms 46592 KB Output is correct
45 Correct 287 ms 32248 KB Output is correct
46 Correct 213 ms 44588 KB Output is correct
47 Correct 216 ms 46952 KB Output is correct
48 Correct 514 ms 46728 KB Output is correct
49 Correct 504 ms 44900 KB Output is correct
50 Correct 530 ms 46352 KB Output is correct
51 Correct 270 ms 40952 KB Output is correct
52 Correct 273 ms 40952 KB Output is correct
53 Correct 259 ms 41016 KB Output is correct
54 Correct 268 ms 40988 KB Output is correct
55 Correct 641 ms 46596 KB Output is correct
56 Correct 309 ms 41236 KB Output is correct
57 Correct 273 ms 30456 KB Output is correct
58 Correct 375 ms 36036 KB Output is correct
59 Correct 367 ms 35272 KB Output is correct
60 Correct 359 ms 32204 KB Output is correct
61 Correct 387 ms 36292 KB Output is correct
62 Correct 380 ms 35656 KB Output is correct
63 Correct 385 ms 35592 KB Output is correct
64 Correct 361 ms 35404 KB Output is correct
65 Correct 374 ms 32868 KB Output is correct
66 Correct 619 ms 46364 KB Output is correct
67 Correct 348 ms 33736 KB Output is correct
68 Correct 248 ms 60820 KB Output is correct
69 Correct 271 ms 60952 KB Output is correct
70 Correct 587 ms 46268 KB Output is correct
71 Correct 557 ms 46044 KB Output is correct
72 Correct 581 ms 46572 KB Output is correct
73 Correct 298 ms 41236 KB Output is correct
74 Correct 296 ms 41196 KB Output is correct
75 Correct 299 ms 41244 KB Output is correct
76 Correct 298 ms 41332 KB Output is correct
77 Correct 668 ms 46768 KB Output is correct
78 Correct 332 ms 40976 KB Output is correct
79 Correct 392 ms 36236 KB Output is correct
80 Correct 381 ms 35912 KB Output is correct
81 Correct 386 ms 36296 KB Output is correct
82 Correct 405 ms 39360 KB Output is correct
83 Correct 406 ms 39624 KB Output is correct
84 Correct 395 ms 36460 KB Output is correct
85 Correct 414 ms 36084 KB Output is correct
86 Correct 383 ms 35912 KB Output is correct
87 Correct 423 ms 36164 KB Output is correct
88 Correct 725 ms 46352 KB Output is correct
89 Correct 438 ms 36288 KB Output is correct
90 Correct 305 ms 60948 KB Output is correct
91 Correct 297 ms 53520 KB Output is correct
92 Correct 692 ms 46712 KB Output is correct
93 Correct 732 ms 45444 KB Output is correct
94 Correct 672 ms 46196 KB Output is correct
95 Correct 338 ms 41200 KB Output is correct
96 Correct 345 ms 41104 KB Output is correct
97 Correct 330 ms 40980 KB Output is correct
98 Correct 335 ms 41072 KB Output is correct