Submission #116579

#TimeUsernameProblemLanguageResultExecution timeMemory
116579dragonslayeritTropical Garden (IOI11_garden)C++14
100 / 100
254 ms48504 KiB
#include "garden.h"
#include "gardenlib.h"
#include <vector>
#include <queue>
#include <cstdio>
#include <algorithm>

const int INF=1e9+7;

static std::vector<int> adj[150005];
static int to[300005];
static std::vector<int> from[300005];

static int dist[2][300005];

static std::vector<int> at[2][300005];

static void bfs(int start,int* dist){
  std::queue<int> q;
  q.push(start);
  while(!q.empty()){
    int node=q.front();
    q.pop();
    for(int child:from[node]){
      if(!dist[child]){
	dist[child]=dist[node]+1;
	q.push(child);
      }
    }
  }
}

void count_routes(int N, int M, int P, int R[][2], int Q, int G[])
{
  for(int i=0;i<M;i++){
    adj[R[i][0]].push_back(R[i][1]);
    adj[R[i][1]].push_back(R[i][0]);
  }
  for(int i=0;i<N;i++){
    to[i<<1]=(adj[i][0]<<1)|(i==adj[adj[i][0]][0]);
    if(adj[i].size()>1){
      to[i<<1|1]=(adj[i][1]<<1)|(i==adj[adj[i][1]][0]);
    }else{
      to[i<<1|1]=to[i<<1];
    }
  }
  for(int i=0;i<N*2;i++){
    from[to[i]].push_back(i);
  }
  bfs(P<<1,dist[0]);
  bfs(P<<1|1,dist[1]);
  int cycle[2];
  cycle[0]=dist[0][P<<1]?dist[0][P<<1]:INF;
  cycle[1]=dist[1][P<<1|1]?dist[1][P<<1|1]:INF;
  for(int d=0;d<2;d++){
    for(int i=0;i<N*2;i+=2){
      if(dist[d][i]){
	at[d][dist[d][i]%cycle[d]].push_back(dist[d][i]);
      }
    }
  }
  for(int d=0;d<2;d++){
    for(int i=0;i<N*2;i++){
      std::sort(at[d][i].begin(),at[d][i].end());
    }
  }
  for(int q=0; q<Q; q++){
    int K=G[q];
    int ans=0;
    /*
    for(int i=0;i<N*2;i+=2){
      if(dist[0][i]) ans+=(K>=dist[0][i]&&(K-dist[0][i])%cycle[0]==0);
      if(dist[1][i]) ans+=(K>=dist[1][i]&&(K-dist[1][i])%cycle[1]==0);
    }
    */
    for(int d=0;d<2;d++){
      int rem=K%cycle[d];
      if(rem<N*2){
	ans+=std::upper_bound(at[d][rem].begin(),at[d][rem].end(),K)-at[d][rem].begin();
      }
    }
    answer(ans);
  }
}


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