Submission #964333

#	Time	Username	Problem	Language	Result	Execution time	Memory
964333		Requiem	Parkovi (COCI22_parkovi)	C++17	20 / 110	1140 ms	37320 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], pre[MAXN];

    bool inter(ii a, ii b){
        return !(a.fi > b.se or a.se < b.fi);
    }
    bool check(int mid){
         for(int i = 1; i < n; i++){
             pre[i] = pre[i - 1] + edge[i].fi;
//             cout << pre[i] << ' ';
         }
//         cout << endl;
         vector<ii> Ranges;
         for(int i = 1; i <= n; i++){
             int lo = 1, hi = i, leftboard = 0;
             while(lo <= hi){
                int m = (lo + hi) / 2;
                if (pre[i - 1] - pre[m - 1] <= mid){
                    leftboard = m;
                    hi = m - 1;
                }
                else lo = m + 1;
             }
             lo = i, hi = n;
             int rightboard = 0;
             while(lo <= hi){
                int m = (lo + hi) / 2;
                if (pre[m - 1] - pre[i - 1] <= mid){
//                    cout << mid << ' ' << pre[mid - 1] - pre[i - 1] << ' ' << mid << endl;
                    rightboard = m;
                    lo = m + 1;
                }
                else hi = m - 1;
             }
//             cout << i << ' ' <<  leftboard << ' ' << rightboard << endl;
             Ranges.pb({leftboard, rightboard});
         }
         sort(Ranges.begin(), Ranges.end());
         int numgroup  = 0;
         for(int l = 0, last = 0; l < Ranges.size(); l = last + 1){
             last = l;
             ii intersect = Ranges[l];
             while(last < Ranges.size() - 1 and inter(intersect, Ranges[last + 1])){
                   last++;
                   intersect = ii(max(intersect.fi, Ranges[last].fi),
                                  min(intersect.se, Ranges[last].se));
             }
             numgroup++;
         }
         return numgroup <= k;
    }
    void SolveSubtask3(){
        int l = 1;
        int r = 1e18;
        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:171:37: warning: comparison of integer expressions of different signedness: 'long long int' and 'std::vector<std::pair<long long int, long long int> >::size_type' {aka 'long unsigned int'} [-Wsign-compare]
  171 |          for(int l = 0, last = 0; l < Ranges.size(); l = last + 1){
      |                                   ~~^~~~~~~~~~~~~~~
Main.cpp:174:25: warning: comparison of integer expressions of different signedness: 'long long int' and 'std::vector<std::pair<long long int, long long int> >::size_type' {aka 'long unsigned int'} [-Wsign-compare]
  174 |              while(last < Ranges.size() - 1 and inter(intersect, Ranges[last + 1])){
      |                    ~~~~~^~~~~~~~~~~~~~~~~~~
Main.cpp: At global scope:
Main.cpp:230:1: warning: ISO C++ forbids declaration of 'main' with no type [-Wreturn-type]
  230 | main()
      | ^~~~
Main.cpp: In function 'int main()':
Main.cpp:234:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
  234 |         freopen(TASKNAME".inp","r",stdin);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~
Main.cpp:235:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
  235 |         freopen(TASKNAME".out","w",stdout);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~

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