Cod sursa(job #1341698)

Utilizator bugyBogdan Vlad bugy Data 13 februarie 2015 00:14:31
Problema Arbori indexati binar Scor 10
Compilator java Status done
Runda Arhiva educationala Marime 2.91 kb
import java.io.BufferedReader;
import java.io.BufferedWriter;
import java.io.FileReader;
import java.io.FileWriter;
import java.io.IOException;

/**
 * 
 * @author bugyvlad
 * 
 */

public class Main {

	public static int N, M;
	public static int[] v,aib;
	
	/*
	 * Citire
	 */
	public static BufferedReader citireFisier() throws IOException {
		BufferedReader fin = new BufferedReader(new FileReader("aib.in"));
		String line = fin.readLine();
			
		String[] numbers = line.split(" ");
		N = Integer.parseInt(numbers[0]);
		M = Integer.parseInt(numbers[1]);
		
		line = fin.readLine();
		numbers = line.split(" ");
		v = new int[numbers.length+1]; //Vectorul cu valorile initiale
		aib = new int[numbers.length+1]; //AIB
		
		for (int i = 1; i <= N; i++) {
			v[i] = Integer.parseInt(numbers[i-1]);
			//Construim vectorul pentru arborele indexat binar
			aib[i] += v[i];
			int index = i; 
			while (true) {
					index += (index&(-index));
					if (index <= numbers.length) {
						aib[index] += v[i];
					} else {
						break;
					}
			}
		}
		return fin;
	}
	
	/*
	 * Adauga b la pozitia a.
	 */
	public static void adaugaLaPoz(int a, int b) {
		v[a] += b;
		int index = a;
		while (true) {
			index += (index&(-index));
			if (index <= N) {
				aib[index] += b;
			} else {
				break;
			}
		}
	}
	
	/*
	 * Suma elementelor din intervalul [1,poz]
	 */
	public static int suma(int poz) {
		int suma = 0;
		while (poz > 0) {
			suma += aib[poz];
			poz -= (poz&(-poz));
		}
		return suma;
	}
	
	/*
	 * Cautare binara pentru suma value.
	 */
	public static int cautareBinara(int left, int right, int value) {
		
		int mij = (left+right)/2;
		int valMij = suma(mij);
		
		if (left > right) {
			return -1;
		}
		if (valMij == value) {
			int k = mij; //Salvam pozitia k si verificam daca exista o pozitie k mai mica.
			
			for (int index = mij-1; index >= 1; index--) {
				if (suma(index) == value) {
					k = index;
				}
			}
			return k;
		} else if (valMij > value) {
			return cautareBinara(left, mij-1, value);
		} else {
			return cautareBinara(mij+1, right, value);
		}
	}
	
	public static void main(String[] args) throws IOException {
		
		BufferedReader fin = citireFisier();
		BufferedWriter fout = new BufferedWriter(new FileWriter("aib.out"));
		
		String line;
		String[] numbers;
		
		for (int t = 0; t < M; t++) {
			line = fin.readLine();
			numbers = line.split(" ");
			if (numbers[0].compareTo("0") == 0) {
				adaugaLaPoz(Integer.parseInt(numbers[1]), Integer.parseInt(numbers[2]));						
			} else if (numbers[0].compareTo("1") == 0) {
				fout.write(Integer.toString(suma(Integer.parseInt(numbers[2])) - suma(Integer.parseInt(numbers[1])-1)));
				fout.write("\n");;
			} else {
				fout.write(Integer.toString(cautareBinara(1, N, Integer.parseInt(numbers[1]))));
				fout.write("\n");;
			}
		}
		fout.close();	
	}
}