Submission #933488

#	Time	Username	Problem	Language	Result	Execution time	Memory
933488		NourWael	Regions (IOI09_regions)	C++17	95 / 100	3219 ms	131072 KiB

regions

#include <bits/stdc++.h>
#define int long long
using namespace std; 
int const mxN = 2e5+5;
int  const mxR = 25005;
vector<int> adj [mxN];
int in[mxN], out[mxN], t, r , n, region[mxN], q, cnt[mxR], c;
map<pair<int,int>,int> fin;
vector<pair<int,int>> reg [mxR];
vector<int> pre;
void dfs ( int i, int p ) {
     in[i] = t, t++;
     for(auto it:adj[i]){
      if(it==p) continue;
      dfs(it,i);
     }
     t++, out[i] = t;
     reg[region[i]].push_back({in[i],out[i]});
}
 
void dfs2 ( int i, int p ) {
     for(int j=0; j<pre.size(); j++) {
        if(region[i]==pre[j]) continue;
        fin[{pre[j],region[i]}] += cnt[pre[j]];
      }
     cnt[region[i]]++;
     for(auto it:adj[i]){
      if(it==p) continue;
      dfs2(it,i);
     }
     cnt[region[i]]--;
 
}
signed main() {
   
   ios_base:: sync_with_stdio(0);
   cin.tie(NULL);
   cout.tie(NULL);
 
   cin>>n>>r>>q>>region[1];
   c = sqrt(n); c++;
   for(int i=2; i<=n; i++) {
      int k, h; cin>>k>>h;
      adj[i].push_back(k), adj[k].push_back(i);
      region[i] = h;
   }
 
   dfs(1,0);
   for(int i=1; i<=r; i++) {
      sort(reg[i].begin(),reg[i].end());
      if(reg[i].size()>=c) pre.push_back(i);
   }
   dfs2(1,0);
   for(int i=0; i<q; i++) {
      int x,y; cin>>x>>y;
      int ans = 0;
      if(reg[x].size()>=c) { cout<<fin[{x,y}]<<endl; continue; }
      for(auto it:reg[x]) {
         int ind1 = lower_bound(reg[y].begin(),reg[y].end(), it ) - reg[y].begin();
         int ind2 = lower_bound(reg[y].begin(),reg[y].end(), make_pair(it.second, 0ll) ) - reg[y].begin();
         ans += ind2-ind1;
      }
      cout<<ans<<endl;
   }
  return 0;
 
}

Compilation message (stderr)

regions.cpp: In function 'void dfs2(long long int, long long int)':
regions.cpp:22:20: warning: comparison of integer expressions of different signedness: 'long long int' and 'std::vector<long long int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   22 |      for(int j=0; j<pre.size(); j++) {
      |                   ~^~~~~~~~~~~
regions.cpp: In function 'int main()':
regions.cpp:51:23: warning: comparison of integer expressions of different signedness: 'std::vector<std::pair<long long int, long long int> >::size_type' {aka 'long unsigned int'} and 'long long int' [-Wsign-compare]
   51 |       if(reg[i].size()>=c) pre.push_back(i);
      |          ~~~~~~~~~~~~~^~~
regions.cpp:57:23: warning: comparison of integer expressions of different signedness: 'std::vector<std::pair<long long int, long long int> >::size_type' {aka 'long unsigned int'} and 'long long int' [-Wsign-compare]
   57 |       if(reg[x].size()>=c) { cout<<fin[{x,y}]<<endl; continue; }
      |          ~~~~~~~~~~~~~^~~

• Subtask 1: 15 / 15
• Subtask 2: 80 / 85