Submission #964314

#	Time	Username	Problem	Language	Result	Execution time	Memory
964314		Requiem	Parkovi (COCI22_parkovi)	C++17	20 / 110	165 ms	41080 KiB

Main

#include<bits/stdc++.h>
#define int long long
#define pb push_back
#define fast ios_base::sync_with_stdio(false), cin.tie(nullptr), cout.tie(nullptr);
#define MOD 1000000007
#define INF 1e18
#define fi first
#define se second
#define endl "\n"
#define FOR(i,a,b) for(int i=a;i<=b;i++)
#define FORD(i,a,b) for(int i=a;i>=b;i--)
#define sz(a) ((int)(a).size())
#define pi 3.14159265359
#define TASKNAME "parkovi"
template<typename T> bool maximize(T &res, const T &val) { if (res < val){ res = val; return true; }; return false; } 
template<typename T> bool minimize(T &res, const T &val) { if (res >= val){ res = val; return true; }; return false; } 
using namespace std; 
typedef pair<int,int> ii; 
typedef pair<int,ii> iii; 
typedef vector<int> vi;
const int MAXN = 3e5 + 9;
vector<int> g[MAXN];
iii edge[MAXN];
int n, k;

namespace sub1{
    bool checkSubtask1(){
        return n <= 20;
    }
    int dist[21];
    vector<int> SetVertice;
    void bfs(){
        priority_queue<ii, vector<ii>, greater<ii> > q;
        fill(dist + 1, dist + 1 + n, INF);
        for(auto x: SetVertice){
            dist[x] = 0;
            q.push({0, x});
        }

        while(!q.empty()){
              int u = q.top().se;
              int du = q.top().fi;
              q.pop();
              if (du > dist[u]) continue;
              for(auto idedge: g[u]){
                  int v = edge[idedge].se.fi + edge[idedge].se.se - u;
                  int w = edge[idedge].fi;
                  if (dist[v] > dist[u] + w){
                      dist[v] = dist[u] + w;
                      q.push({dist[v], v});
                  }
              }
        }
    }

    void solveSubtask1(){
         int res = INF;
         int msk = 0;
         for(int i = 1; i < (1 << n); i++){
             SetVertice.clear();
             if (__builtin_popcount(i) != k) continue;
             for(int j = 0; j < n; j++){
                 if (i & (1 << j)) SetVertice.pb(j + 1);
             }
             bfs();
             if (minimize(res, *max_element(dist + 1, dist + 1 + n))) msk = i;
         }
         cout << res << endl;
         vector<int> park;
         for(int i = 0; i < n; i++){
             if (msk & (1 << i)) park.pb(i + 1);
         }
         for(auto x: park){
             cout << x << " ";
         }
         cout << endl;
    }
}

namespace sub2{
    bool checkSubtask2(){
        return k == 1;
    }

    int par[MAXN], depth[MAXN];
    void dfs(int u,int p){
        for(auto idedge: g[u]){
            int v = edge[idedge].se.fi + edge[idedge].se.se - u;
            int w = edge[idedge].fi;
            if (v == p) continue;
            depth[v] = depth[u] + w;
            par[v] = u;
            dfs(v, u);
        }
    }

    void reset(){
         fill(par + 1, par + 1 + n, -1);
         fill(depth + 1, depth + 1 + n, 0);
    }

    void solveSubtask2(){
         dfs(1, -1);
         int root = max_element(depth + 1, depth + 1 + n) - depth;
         reset();
         dfs(root, -1);
         int furthest = max_element(depth + 1, depth + 1 + n) - depth;
         
         vector<int> diameter;
         int res = INF, tmp = furthest, chosen = 0;
         while(tmp != root) {
               if (minimize(res, max(depth[tmp], depth[furthest] - depth[tmp]))){
                   chosen = tmp;
               }
               tmp = par[tmp];
         }

         cout << res << endl;
         cout << chosen << endl;

         
    }
}

namespace sub3{
    bool checkSubtask3(){
        for(int i = 1; i < n; i++){
            if (edge[i].se.fi != i or edge[i].se.se != i + 1) return false;
        }
        return true;
    }

    int chosen[MAXN];

    bool check(int mid){
        int minimum = 0;
        queue<int> q;
        q.push(1);
        int tmp = k;
        int cur = mid;
        while(!q.empty()){
            int u = q.front();
            // cout << u << ' ' << cur << endl;
            if (cur < 0){
                cur = mid;
                tmp--;
            }
            q.pop();
            for(auto idedge: g[u]){
                int v = edge[idedge].se.fi + edge[idedge].se.se - u;
                int w = edge[idedge].fi;
                if (v == u - 1) continue;
                if (cur - w < 0){
                    tmp--;
                    cur = mid - w;
                }
                else cur = cur - w;
                q.push(v);
            }
        }
        return tmp >= 0;
    }
    void SolveSubtask3(){
        int l = 1;
        int r = 2e14;
        int res= 0;
        while(l <= r){
            int mid = (l + r) >> 1;
            if (check(mid)) {
                res = mid;
                r = mid - 1;
            }
            else l = mid + 1;
        }
        queue<int> q;
        q.push(1);
        int cur = res;
        while(!q.empty()){
            int u = q.front();
            q.pop();
            if (cur < 0){
                cur = res;
                k--;
                chosen[u] = 1;
            }
            for(auto idedge: g[u]){
                int v = edge[idedge].se.fi + edge[idedge].se.se - u;
                int w = edge[idedge].fi;
                if (v == u - 1) continue;
                if (cur - w < 0){
                    k--;
                    cur = res - w;
                    chosen[u] = 1;
                }
                else cur -= w;
                q.push(v);
            }
        }

        for(int i = 1; i <= n; i++){
            if (!chosen[i] and k > 0) chosen[i] = 1, k--;
        }
        cout << res << endl;
        for(int i = 1; i <= n; i++){
            if (chosen[i]) cout << i << " ";
        }
        cout << endl;
    }
}
main() 
{ 
    fast; 
   if (fopen(TASKNAME".inp","r")){
        freopen(TASKNAME".inp","r",stdin); 
        freopen(TASKNAME".out","w",stdout); 
   } 
   cin >> n >> k;
   for(int i = 1; i < n; i++){ 
       int u, v, w;
       cin >> u >> v >> w;
       edge[i] = {w, {u, v}};
       g[u].pb(i);
       g[v].pb(i);
   }

   if (sub1::checkSubtask1()) return sub1::solveSubtask1(), 0;
   if (sub2::checkSubtask2()) return sub2::solveSubtask2(), 0;
   if (sub3::checkSubtask3()) return sub3::SolveSubtask3(), 0;
} 

Compilation message (stderr)

Main.cpp: In function 'bool sub3::check(long long int)':
Main.cpp:136:13: warning: unused variable 'minimum' [-Wunused-variable]
  136 |         int minimum = 0;
      |             ^~~~~~~
Main.cpp: At global scope:
Main.cpp:210:1: warning: ISO C++ forbids declaration of 'main' with no type [-Wreturn-type]
  210 | main()
      | ^~~~
Main.cpp: In function 'int main()':
Main.cpp:214:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
  214 |         freopen(TASKNAME".inp","r",stdin);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~
Main.cpp:215:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
  215 |         freopen(TASKNAME".out","w",stdout);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~

• Subtask 1: 10 / 10
• Subtask 2: 10 / 10
• Subtask 3: 0 / 30
• Subtask 4: 0 / 60