Cod sursa(job #287991)

Utilizator whiskeyOzzy Osbourne whiskey Data 25 martie 2009 13:59:49
Problema Arbori de intervale Scor 100
Compilator cpp Status done
Runda Arhiva educationala Marime 1.37 kb
#include <stdio.h>
#include <vector>
using namespace std;

int n, pos, val, maxim, seq_start, seq_end;
vector<int> arb;

void solve();
void update(int, int, int);
void query(int, int, int);
inline int max(int, int);

int main()
{
	solve();
	return 0;
}

void solve()
{
	int i, m, x, y, z;
	FILE *fin = fopen("arbint.in", "r");
	FILE *fout = fopen("arbint.out", "w");
	fscanf(fin, "%d%d", &n, &m);
	arb.resize(4 * n, 0);

	for (pos = 1; pos <= n; ++pos)
	{
		fscanf(fin, "%d", &val);
		update(1, 1, n);
	}

	for (i = 1; i <= m; ++i)
	{
		fscanf(fin, "%d%d%d", &x, &y, &z);
		if (x)
		{
			pos = y;
			val = z;
			update(1, 1, n);
		}
		else
		{
			maxim = 0;
			seq_start = y;
			seq_end = z;
			query(1, 1, n);
			fprintf(fout, "%d\n", maxim);
		}
	}

	fclose(fin);
	fclose(fout);
}

void query(int nod, int st, int dr)
{
	if (seq_start <= st && dr <= seq_end)
	{
		maxim = max(maxim, arb[nod]);
	}
	else
	{
		int mid = (st + dr) / 2;

		if (seq_start <= mid)
		{
			query(2 * nod, st, mid);
		}
		if (mid < seq_end)
		{
			query(2 * nod + 1, mid + 1, dr);
		}
	}
}

void update(int nod, int st, int dr)
{
	if (st == dr)
	{
		arb[nod] = val;
	}
	else
	{
		int mid = (st + dr) / 2;
		if (pos <= mid)
		{
			update(2 * nod, st, mid);
		}
		else
		{
			update(2 * nod + 1, mid + 1, dr);
		}
		arb[nod] = max(arb[2*nod], arb[2*nod+1]);
	}
}

inline int max(int a, int b)
{
	return ((a > b) ? a : b);
}