Cod sursa(job #1418906)

Utilizator phobosJustin Lim Kai Ze phobos Data 14 aprilie 2015 13:03:57
Problema Range minimum query Scor 30
Compilator cpp Status done
Runda Arhiva educationala Marime 0.81 kb
#include <iostream>
#include <cstdio>
#include <algorithm>
#include <cmath>
using namespace std;
const int MX = 1e5+1;
int st[MX][17], A[MX], n, m;

int main() {
	ios_base::sync_with_stdio(false);
	freopen ("rmq.in", "r", stdin);
	freopen ("rmq.out", "w", stdout);
	cin >> n >> m;
	for (int i = 0; i < n; i++) {
		cin >> A[i];
		st[i][0] = A[i];
	}
	for (int i = 1; (1 << i) <= n; i++) {
		for (int j = 0; j + (1 << i) - 1 < n; j++) {
			st[j][i] = min(st[j][i-1], st[j + (1 << (i-1))][i-1]);
		}
	}
	int x, y, lg[MX];
	lg[1] = 0;
	for (int i = 2; i <= n; i++) {
		if ((1 << (lg[i-1]+1)) > i) lg[i] = lg[i-1];
		else lg[i] = lg[i-1]+1;
	}
	for (int i = 0; i < m; i++) {
		cin >> x >> y;
		x--, y--;
		int k = lg[y-x+1];
		cout << min(st[x][k], st[y - (1 << k) + 1][k]) << '\n';
	}
	return 0;
}