Submission #211744

#	Time	Username	Problem	Language	Result	Execution time	Memory
211744		Lawliet	Regions (IOI09_regions)	C++17	25 / 100	8096 ms	131076 KiB

regions

#include <bits/stdc++.h>

using namespace std;
typedef long long int lli;
typedef pair<int,int> pii;

const int MAXN = 200010;

class FenwickTree
{
	public:

		void update(int i, int v)
		{
			for( ; i < MAXN ; i += i & -i )
				BIT[i] += v;
		}

		int query(int i)
		{
			int ans = 0;

			for( ; i > 0 ; i -= i & -i )
				ans += BIT[i];

			return ans;
		}

		int sum(int L, int R) { return query(R) - query(L - 1); }

		FenwickTree() { memset( BIT , 0 , sizeof(BIT) ); }

	private:

		int BIT[MAXN];
};

int n, r, q;
int curTime;

int v[MAXN];
int freq[MAXN];

int sub[MAXN];
int tin[MAXN];
int tout[MAXN];
int prof[MAXN];

int indHeavy[MAXN];
int upAnswer[MAXN];
int downAnswer[MAXN];

bool isHeavy[MAXN];

vector< int > adj[MAXN];
vector< int > nodes[MAXN];
vector< int > ansHeavy[MAXN];

FenwickTree BIT;

void DFSInit(int cur)
{
	tin[cur] = ++curTime;

	for(int i = 0 ; i < adj[cur].size() ; i++)
		DFSInit( adj[cur][i] );

	tout[cur] = curTime;
}

void DFSCalculate(int cur, int heavyRegion)
{
	sub[cur] = 0;

	if( v[cur] == heavyRegion )
	{
		sub[cur]++;
		prof[cur]++;
	}

	for(int i = 0 ; i < adj[cur].size() ; i++)
	{
		int viz = adj[cur][i];
		
		prof[viz] = prof[cur];

		DFSCalculate( viz , heavyRegion );

		sub[cur] += sub[viz];
	}
}

int lightQuery(int A, int B)
{
	for(int i = 0 ; i < nodes[B].size() ; i++)
		BIT.update( tin[ nodes[B][i] ] , 1 );

	int ans = 0;

	for(int i = 0 ; i < nodes[A].size() ; i++)
		ans += BIT.sum( tin[ nodes[A][i] ] , tout[ nodes[A][i] ] );

	for(int i = 0 ; i < nodes[B].size() ; i++)
		BIT.update( tin[ nodes[B][i] ] , -1 );

	return ans;
}

int main()
{
	scanf("%d %d %d",&n,&r,&q);

	double aux = r;
	aux /= log2( r );

	int T = sqrt( aux ) + 1;

	scanf("%d",&v[1]);

	for(int i = 2 ; i <= n ; i++)
	{
		int p;
		scanf("%d %d",&p,&v[i]);

		adj[p].push_back( i );
	}

	for(int i = 1 ; i <= n ; i++)
	{
		freq[ v[i] ]++;
		nodes[ v[i] ].push_back( i );
	}

	int curInd = 0;

	for(int i = 1 ; i <= r ; i++)
	{
		if( freq[i] < T ) continue;

		isHeavy[i] = true;
		indHeavy[i] = ++curInd;

		prof[1] = 0;
		DFSCalculate( 1 , i );

		for(int j = 1 ; j <= n ; j++)
		{
			upAnswer[ v[j] ] += prof[j];
			downAnswer[ v[j] ] += sub[j];
		}

		for(int j = 1 ; j <= r ; j++)
			ansHeavy[curInd].push_back( upAnswer[j] );

		for(int j = 1 ; j <= r ; j++)
			ansHeavy[curInd].push_back( downAnswer[j] );

		for(int j = 1 ; j <= r ; j++)
			upAnswer[j] = downAnswer[j] = 0;
	}

	for(int i = 1 ; i <= q ; i++)
	{
		int A, B;
		scanf("%d %d",&A,&B);

		if( !isHeavy[A] && !isHeavy[B] ) printf("%d\n",lightQuery( A , B ));
		else
		{
			if( isHeavy[A] )
			{
				int ind = indHeavy[A];
				printf("%d\n",ansHeavy[ind][B - 1]);
			}
			else
			{
				int ind = indHeavy[B];
				printf("%d\n",ansHeavy[ind][A - 1 + r]);
			}
		}

		fflush( stdout );
	}
}

Compilation message (stderr)

regions.cpp: In function 'void DFSInit(int)':
regions.cpp:65:20: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
  for(int i = 0 ; i < adj[cur].size() ; i++)
                  ~~^~~~~~~~~~~~~~~~~
regions.cpp: In function 'void DFSCalculate(int, int)':
regions.cpp:81:20: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
  for(int i = 0 ; i < adj[cur].size() ; i++)
                  ~~^~~~~~~~~~~~~~~~~
regions.cpp: In function 'int lightQuery(int, int)':
regions.cpp:95:20: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
  for(int i = 0 ; i < nodes[B].size() ; i++)
                  ~~^~~~~~~~~~~~~~~~~
regions.cpp:100:20: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
  for(int i = 0 ; i < nodes[A].size() ; i++)
                  ~~^~~~~~~~~~~~~~~~~
regions.cpp:103:20: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
  for(int i = 0 ; i < nodes[B].size() ; i++)
                  ~~^~~~~~~~~~~~~~~~~
regions.cpp: In function 'int main()':
regions.cpp:111:7: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
  scanf("%d %d %d",&n,&r,&q);
  ~~~~~^~~~~~~~~~~~~~~~~~~~~
regions.cpp:118:7: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
  scanf("%d",&v[1]);
  ~~~~~^~~~~~~~~~~~
regions.cpp:123:8: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
   scanf("%d %d",&p,&v[i]);
   ~~~~~^~~~~~~~~~~~~~~~~~
regions.cpp:165:8: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
   scanf("%d %d",&A,&B);
   ~~~~~^~~~~~~~~~~~~~~

• Subtask 1: 10 / 15
• Subtask 2: 15 / 85