Cod sursa(job #990396)

Utilizator harababurelPuscas Sergiu harababurel Data 28 august 2013 10:19:16
Problema Arbori de intervale Scor 50
Compilator cpp Status done
Runda Arhiva educationala Marime 1.1 kb
#include <iostream>
#include <fstream>
#define nmax 100005
using namespace std;

int arb[5*nmax];
int n, m, op, x, y, pos, val, sol;

void update(int nod, int st, int dr) {
	if(st == dr) {
		arb[nod] = val;
		return;
	}

	int mij = (st + dr) >> 1;

	if(pos <= mij) update(2*nod, st, mij);
	else update(2*nod+1, mij+1, dr);

	arb[nod] = max(arb[2*nod], arb[2*nod+1]);
}

void query(int nod, int st, int dr, int a, int b) {
	//<nod> reprezinta intervalul [<st>, <dr>]
	//trebuie sa updatez intervalul [<a>, <b>]

	if(a <= st && b >= dr) {
		sol = max(sol, arb[nod]);
		return;
	}

	int mij = (st + dr) >> 1, maxim = 0;
	if(a <= mij)   query(2*nod, st, mij, a, b);
	if(mij+1 <= b) query(2*nod+1, mij+1, dr, a, b);
}

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

	f>>n>>m;
	for(int i=1; i<=n; i++) {
		f>>x;
		pos = i;
		val = x;
		update(1, 1, n);
	}

	for(int i=1; i<=m; i++) {
		f>>op>>x>>y;
		if(op == 1) {
			pos = x;
			val = y;
			update(1, 1, n);
		}
		else {
			sol = 0;
			query(1, 1, n, x, y);
			g<<sol<<"\n";
		}
	}

	return 0;
}