Submission #565932

#	Time	Username	Problem	Language	Result	Execution time	Memory
565932		birthdaycake	Evacuation plan (IZhO18_plan)	C++17	100 / 100	1069 ms	70324 KiB

plan

#include<bits/stdc++.h>
#define endl '\n'
#define mod 1000000007
#define boost ios_base::sync_with_stdio(false), cin.tie(NULL);
using namespace std;
 
 
 
vector<pair<int,int>>adj[200001];
int dist[200001],npp[200001];
vector<pair<int,int>> queries[200001];
 
vector<int> cmp[200001]; int vs[200001],cm[200001], ans[200001];
 
 
 

void merge(int a, int b, int dg){
    
    if(cm[a] == cm[b]) return;
    
    if(cmp[cm[a]].size() > cmp[cm[b]].size()) swap(a,b);
    for(auto s: cmp[cm[a]]){
        for(auto f : queries[s]){
            if(cm[f.first] == cm[b]) ans[f.second] = dg;
        }
    }
    for(auto s: cmp[cm[a]]){
        cm[s] = cm[b];
        cmp[cm[b]].push_back(s);
    }

}
signed main(){
    boost;
    
    int n,m; cin >> n >> m;
    set<pair<int,int>>d;
    for(int i = 0; i < m; i++){
        int a,b,c; cin >> a >> b >> c;
        adj[a].push_back({b,c});
        adj[b].push_back({a,c});
        if(a > b) swap(a,b);
        d.insert({a,b});
    }
    
    int k; cin >> k;
    set<pair<int,int>>bfs;
    
    for(int i = 1; i <= n; i++) npp[i] = INT_MAX;
 
    
    
    for(int i = 1; i <= k; i++) {
        int x; cin >> x;
        npp[x] = 0;
        bfs.insert({0,x});
    }
    
    while(bfs.size()){
        auto x = *bfs.begin();
        bfs.erase(x);
        if(npp[x.second] < x.first) continue;
        for(auto s : adj[x.second]){
            if(npp[x.second] + s.second < npp[s.first]){
                npp[s.first] = npp[x.second] + s.second;
                bfs.insert({npp[s.first], s.first});
            }
        }
    }
   
    int q; cin >> q;
    for(int i = 0; i < q; i++){
        int a,b; cin >> a >> b;
        queries[a].push_back({b,i});
        queries[b].push_back({a,i});
    }
    vector<pair<int,int>>x;
    for(int i = 1; i <= n; i++){
        cm[i] = i;
        cmp[i].push_back(i);
        x.push_back({npp[i],i});
    }
    
    sort(x.begin(), x.end(), greater<pair<int,int>>());
    for(int i = 0; i < x.size(); i++){
        int k = x[i].second;
        for(auto s: adj[k]){
            if(vs[s.first]){
                merge(k,s.first,x[i].first);
            }
        }
        
        vs[k] = 1;
    }
    for(int i = 0; i < q; i++)cout << ans[i] << endl;
   
    return 0;
}

Compilation message (stderr)

plan.cpp: In function 'int main()':
plan.cpp:86:22: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<std::pair<int, int> >::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   86 |     for(int i = 0; i < x.size(); i++){
      |                    ~~^~~~~~~~~~

• Subtask 1: 10 / 10
• Subtask 2: 13 / 13
• Subtask 3: 12 / 12
• Subtask 4: 19 / 19
• Subtask 5: 46 / 46