Cod sursa(job #1437354)

Utilizator AndupkIonescu Alexandru Andupk Data 17 mai 2015 15:17:26
Problema Arbori de intervale Scor 50
Compilator cpp Status done
Runda Arhiva educationala Marime 1.48 kb
#include <fstream>
#include <algorithm>
#include <iostream>

using namespace std;

void query(int *ai, int nod, int St, int Dr, int st, int dr);
void update(int *ai, int nod, int val, int pos, int st, int dr);
void build(int *ai, int *v, int nod, int st, int dr);

int Max = 0;

int main()
{
	ifstream in("arbint.in");
	ofstream out("arbint.out");

	int ai[100001 * 4 + 1] = {0};
	int v[100005];
	int n, m, x, y, z;
	in>>n>>m;

	for(int i=1; i<=n; ++i)
		in>>v[i];

	build(ai, v, 1, 1, n);

	for(int i=1; i<=m;++i) {
		in>>x>>y>>z;
		if( x == 0){
			Max = 0;
			query(ai, 1, 1,n, y, z);
			out<<Max<<endl;
		}
		else
			update(ai, 1, z, y, 1, n);
	}

	return 0;
}

void build(int *ai, int *v, int nod, int st, int dr)
{
	if( st == dr ) {
		ai[nod] = v[st];
		return;
	}
	
	int mij = (st+dr)>>1;
	build(ai,v, nod<<1, st, mij);
	build(ai, v, (nod<<1) +1, mij+1, dr);
	ai[nod] = max(ai[nod<<1] , ai[(nod<<1) +1]);
}

void update(int *ai, int nod, int val, int pos, int st, int dr)
{

	int mij = (dr + st)>>1;
	if ( st == dr) { 
		ai[nod] = val;
		return;
	}

	if ( mij >= pos  ) 
		update(ai, nod<<1, val, pos, st, mij );
	if ( mij < pos )
		update(ai, (nod<<1) + 1, val, pos, mij+1, dr );
	
	ai[nod] = max( ai[nod*2], ai[nod*2 +1] );
}

void query (int *ai, int nod, int St, int Dr, int st, int dr) {
	int mij = (St + Dr)>>1;
	if ( st <= St && dr >= Dr) {
		Max = max(Max, ai[nod]);
		return;
	}
	if ( mij >= st ) 
		query(ai, nod<<1, St, mij, st, dr);
	if ( mij < dr)
		query(ai, (nod<<1) + 1, mij+1, Dr, st, dr);

}