Cod sursa(job #748899)

Utilizator fhandreiAndrei Hareza fhandrei Data 15 mai 2012 09:06:40
Problema Range minimum query Scor 90
Compilator cpp Status done
Runda Arhiva educationala Marime 1.4 kb
//Include
#include <fstream>
using namespace std;

//Definitii
#define leftSon (node<<1)
#define rightSon (node<<1)+1

//Constante
const int TREE_SIZE = (int)4e5+1;
const int oo = (1<<30) - 1;

//Functii
void update(int node, int left, int right);
void query(int node, int left, int right);

//Variabile
ifstream in("rmq.in");
ofstream out("rmq.out");

int elements, questions;
int position, value;
int leftRange, rightRange;
int minValue;
int tree[TREE_SIZE];

//Main
int main()
{
	in >> elements >> questions;
	for(position=1 ; position<=elements ; ++position)
	{
		in >> value;
		update(1, 1, elements);
	}
	
	while(questions--)
	{
		minValue = oo;
		in >> leftRange >> rightRange;
		query(1, 1, elements);
		out << minValue << '\n';
	}
	
	in.close();
	out.close();
	return 0;
}

void update(int node, int left, int right)
{
	if(left == right)
	{
		tree[node] = value;
		return ;
	}
	
	int mid = (left+right)>>1;
	
	if(position <= mid)
		update(leftSon, left, mid);
	else
		update(rightSon, mid+1, right);
	
	tree[node] = min(tree[leftSon], tree[rightSon]);
}

void query(int node, int left, int right)
{
	if(leftRange <= left && right <= rightRange)
	{
		minValue = min(minValue, tree[node]);
		return ;
	}
	
	int mid = (left+right)>>1;
	if(leftRange <= mid)
		query(leftSon, left, mid);
	if(mid < rightRange)
		query(rightSon, mid+1, right);
}