Submission #116420

#	Time	Username	Problem	Language	Result	Execution time	Memory
116420		kig9981	Regions (IOI09_regions)	C++17	100 / 100	7954 ms	122568 KiB

regions

#include <bits/stdc++.h>
 
#ifdef NON_SUBMIT
#define TEST(n) (n)
#define tout cerr
#else
#define TEST(n) ((void)0)
#define tout cin
#endif
 
using namespace std;

const int rt=448;
vector<int> adj[200000], R[25000], O;
int node_cnt=-1, RV[200000], num[200000], fin[200000], sum[rt][200000], sum2[rt][200000], tree[200001], idx[200000];
long long ans1[rt][25000], ans2[rt][25000];

void add_tree(int n, int v)
{
	for(++n;n<=200000;n+=n&-n) tree[n]+=v;
}

int get_sum(int n)
{
	int ret=0;
	for(++n;n;n-=n&-n) ret+=tree[n];
	return ret;
}

int get_sum(int s, int e)
{
	return get_sum(e)-get_sum(s-1);
}

void dfs(int c)
{
	num[c]=++node_cnt;
	for(auto n: adj[c]) dfs(n);
	fin[c]=node_cnt;
}

void dfs2(int c, int idx)
{
	if(RV[c]==O[idx]) {
		sum[idx][c]++;
		sum2[idx][c]++;
	}
	for(auto n: adj[c]) {
		sum[idx][n]=sum[idx][c];
		dfs2(n,idx);
		sum2[idx][c]+=sum2[idx][n];
	}
}

int main()
{
	ios::sync_with_stdio(false);
	cin.tie(NULL); cout.tie(NULL);
	TEST(freopen("input.txt","r",stdin));
	TEST(freopen("output.txt","w",stdout));
	TEST(freopen("debug.txt","w",stderr));
	int N, M, Q, p;
	cin>>N>>M>>Q>>RV[0];
	R[--RV[0]].push_back(0);
	for(int i=1;i<N;i++) {
		cin>>p>>RV[i];
		adj[--p].push_back(i);
		R[--RV[i]].push_back(i);
	}
	dfs(0);
	for(int i=0;i<M;i++) if(R[i].size()>=rt) {
		idx[i]=O.size();
		O.push_back(i);
		dfs2(0,O.size()-1);
	}
	for(int i=0;i<O.size();i++) for(int j=0;j<N;j++) {
		ans1[i][RV[j]]+=sum[i][j];
		ans2[i][RV[j]]+=sum2[i][j];
	}
	while(Q--) {
		int a, b;
		cin>>a>>b; --a; --b;
		if(R[a].size()>=rt) cout<<ans1[idx[a]][b]<<'\n';
		else if(R[b].size()>=rt) cout<<ans2[idx[b]][a]<<'\n';
		else {
			long long ans=0;
			for(auto r: R[b]) add_tree(num[r],1);
			for(auto r: R[a]) ans+=get_sum(num[r],fin[r]);
			for(auto r: R[b]) add_tree(num[r],-1);
			cout<<ans<<'\n';
		}
		cout.flush();
	}
	return 0;
}

Compilation message (stderr)

regions.cpp: In function 'int main()':
regions.cpp:76:15: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
  for(int i=0;i<O.size();i++) for(int j=0;j<N;j++) {
              ~^~~~~~~~~

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