Cod sursa(job #1361822)

Utilizator vlad.maneaVlad Manea vlad.manea Data 25 februarie 2015 23:57:06
Problema Generare de permutari Scor 100
Compilator java Status done
Runda Arhiva educationala Marime 1.82 kb
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.io.PrintWriter;
import java.util.ArrayList;
import java.util.BitSet;
import java.util.List;
import java.util.Scanner;

class PermutationGenerator {
	private int size;
	List<List<Integer>> solutions;
	List<Integer> solution;
	BitSet visited;
	
	public PermutationGenerator(int size) {
		this.size = size;
	}
	
	public List<List<Integer>> generatePermutations() {
		solutions = new ArrayList<List<Integer>>();
		solution = new ArrayList<Integer>();
		visited = new BitSet(size);
		generatePermutation(0);
		return solutions;
	}
	
	private void generatePermutation(int k) {
		if (k >= size) {
			solutions.add(new ArrayList<Integer>(solution));
			return;
		}
		
		for (int i = 0; i < size; ++i) {
			if (visited.get(i)) {
				continue;
			}
			
			solution.add(i);
			visited.set(i);
			generatePermutation(k + 1);
			visited.clear(i);
			solution.remove(solution.size() - 1);
		}		
	}
}

public class Main {
	public static void main(String[] args) throws IOException {
		InputStream inputStream = new FileInputStream("permutari.in");
		Scanner scanner = new Scanner(inputStream);
		
		OutputStream outputStream = new FileOutputStream("permutari.out");
		PrintWriter writer = new PrintWriter(outputStream);
		
		int N = scanner.nextInt();
		List<List<Integer>> solutions = new PermutationGenerator(N).generatePermutations();
		
		for (List<Integer> solution : solutions) {
			for (int i : solution) {
				writer.print((1 + i) + " ");
			}
			
			writer.println();
		}
		
		writer.flush();
		
		writer.close();
		outputStream.close();
		
		scanner.close();
		inputStream.close();
	}
}