Submission #1079550

#	Time	Username	Problem	Language	Result	Execution time	Memory
1079550		bleahbleah	Comparing Plants (IOI20_plants)	C++17	5 / 100	299 ms	64776 KiB

plants

#include "plants.h"
#include <bits/stdc++.h>
#define all(x) (x).begin(),(x).end()

using namespace std;

using ll = long long;
#define sz(x) ((int)(x).size())

int K, N;
const int nmax = 2e5 + 5;

namespace Queue {
   int next[nmax];
   int inside[nmax];
   
   set<int> heads;
   void insert(int node) {
      heads.emplace(node);
      inside[node] = 1;
      next[node] = -1;
      for(int i = (node + 1) % N, d = 1; i != node && d < K; d++, i = (i + 1) % N) {
         if(inside[i]) {
            if(heads.count(i))
               heads.erase(i);
            next[node] = i;
         }
      }
      for(int i = (node - 1 + N) % N, d = 1; i != node && d < K; d++, i = (i - 1 + N) % N) {
         if(inside[i]) {
            heads.erase(node);
            next[i] = node;
         }
      }
   }
   
   vector<int> prune() {
      vector<int> rez;
      for(auto x : heads)
         rez.emplace_back(x), inside[x] = 0;
      heads.clear();
      for(auto x : rez)
         if(next[x] != -1) heads.emplace(next[x]);
      return rez;
   }
}

vector<int> topsort;
#define left ofia
#define right goa
int left[nmax][18], jumpl[nmax][18];
int right[nmax][18], jumpr[nmax][18];

void init(int k__, std::vector<int> r) {
   K = k__;
   N = sz(r);
   topsort.resize(N);
   
   vector<int> erased(N, 0);
   for(int i = 0; i < sz(r); i++) 
      if(r[i] == 0) erased[i] = 1, Queue::insert(i);
   
   int color = 0;
   while(sz(Queue::heads)) {
      auto rem = Queue::prune();
      //for(auto x : rem) cerr << x << ' ';
      //cerr << '\n';
      ++color;
      for(auto x : rem) topsort[x] = color;
      
      for(auto x : rem) {
         for(int i = (x - 1 + N) % N, d = 1; d < K; d++, i = (i - 1 + N) % N) {
            if(erased[i]) continue;
            r[i]--;
            if(r[i] == 0) erased[i] = 1, Queue::insert(i);
         }
      }
   }
   
   for(int x = 0; x < sz(r); x++) {
      int mn = -1;
      jumpl[x][0] = 0;
      for(int i = (x - 1 + N) % N, d = 1; d < K; d++, i = (i - 1 + N) % N) {
         if(topsort[i] > topsort[x])
            mn = (mn == -1? jumpl[x][0] = d, i : topsort[mn] < topsort[i]? mn : jumpl[x][0] = d, i);
      }
      left[x][0] = mn == -1? x : mn;
      
      mn = -1;
      jumpr[x][0] = 0;
      for(int i = (x + 1 + N) % N, d = 1; d < K; d++, i = (i + 1 + N) % N) {
         if(topsort[i] > topsort[x])
            mn = (mn == -1? jumpr[x][0] = d, i : topsort[mn] < topsort[i]? mn : jumpr[x][0] = d, i);
      }
      right[x][0] = mn == -1? x : mn;
      //cerr << x << ": " << left[x][0] << ' ' << right[x][0] << '\t' << jumpl[x][0] << ' ' << jumpr[x][0] << '\n';
   }
   for(int step = 1; step < 18; step++)
      for(int i = 0; i < N; i++)
         left[i][step] = left[left[i][step - 1]][step - 1], jumpl[i][step] = jumpl[i][step - 1] + jumpl[left[i][step - 1]][step - 1],
         right[i][step] = right[right[i][step - 1]][step - 1], jumpr[i][step] = jumpr[i][step - 1] + jumpr[right[i][step - 1]][step - 1];
   
   //for(auto x : topsort) cerr << x << ' ';
   //cerr << '\n';
   
	return;
}

bool compare_smaller(int x, int y) {
   //cerr << x << " vs " << y << '\n';
   auto rdist = [&](int d) {
      return d < x? N - x + d : d - x;
   };
   auto ldist = [&](int d) {
      return d <= x? x - d : x + N - d;
   };
   
   int st = x, buffer = rdist(y);
   for(int i = 17; i >= 0; i--) {
      if(buffer < jumpr[st][i]) continue;
      buffer -= jumpr[st][i];
      st = right[st][i];
   }
   
   //cerr << "rightmost: " << x << ' ' << st << ' ' << y << "\t\t" << rdist(y) << ' ' << rdist(st) << ' ' << topsort[st] << ' ' << topsort[x] << '\n';
   //for(int i = 0; i < N; i++) cerr << ldist(i) << ' ';
   //cerr << '\n';
   
   if(st == y) return 1;
   if(rdist(y) - rdist(st) < K && topsort[y] > topsort[st]) return 1;
   
   st = x;
   buffer = ldist(y);
   for(int i = 17; i >= 0; i--) {
      if(buffer < jumpl[st][i]) continue;
      buffer -= jumpl[st][i];
      st = left[st][i];
   }
   
   
   //cerr << "leftmost: " << x << ' ' << st << ' ' << y << "\t\t" << ldist(y) << ' ' << ldist(st) << ' ' << topsort[st] << ' ' << topsort[x] << '\n';
   
   if(st == y) return 1;
   if(ldist(y) - ldist(st) < K && topsort[y] > topsort[st]) return 1;
   return 0;
}

int compare_plants(int x, int y) {
   //cerr << x << ' ' << y << '\t' << compare_smaller(x, y) << '\t' << compare_smaller(y, x) << '\n';
   return compare_smaller(x, y)? 1 : compare_smaller(y, x)? -1 : 0;
}

• Subtask 1: 5 / 5
• Subtask 2: 0 / 14
• Subtask 3: 0 / 13
• Subtask 4: 0 / 17
• Subtask 5: 0 / 11
• Subtask 6: 0 / 15
• Subtask 7: 0 / 25