15649~15652_N과 M (1)~(4) (JAVA)

15649_N과 M (1) : 순열

15649번: N과 M (1)

import java.util.ArrayList;
import java.util.Arrays;
import java.util.LinkedList;
import java.util.Scanner;
import java.util.List;

public class Main {
	static int N;
	static int M;
	public static void main(String[] args) throws Exception{
		Scanner sc = new Scanner(System.in);
		N = sc.nextInt();
		M = sc.nextInt();

		List<Integer> num = new ArrayList<Integer>();
		int[] ans = new int[M];
		for(int i=1; i<=N; i++){
			num.add(i);
		}

		int cnt = 0;
		permutation(num, ans, cnt);


	}

	private static void permutation(List<Integer> num, int[] ans, int cnt){
		if(cnt == M){
			String str = Arrays.toString(ans).replaceAll("\\[", "");
			str = str.replaceAll("\\]", "");
			str = str.replace(",", "");
			System.out.println(str);
			return;
		}

		for(int i=0; i<num.size(); i++){
			ans[cnt] = num.remove(i);
			permutation(num, ans, cnt+1);
			num.add(i, ans[cnt]);
		}
	}
}

 

 

15650_N과 M (2) : 조합

15650번: N과 M (2)

import java.util.Scanner;

public class Main {
	static int N;
	static int M;
	public static void main(String[] args){
		Scanner sc = new Scanner(System.in);
		N = sc.nextInt();
		M = sc.nextInt();

		int[] num = new int[N];
		boolean[] checked = new boolean[N];
		for(int i=0; i<N; i++){
			num[i] = i+1;
		}
		makeset(num, checked, 0, 0);
	}
	private static void makeset(int[] num, boolean[] checked, int index, int cnt){
		if(cnt == M){
			for(int i=0; i<num.length; i++){
				if(checked[i])
					System.out.print(num[i]+" ");
			}
			System.out.println();
			return;
		}

		if(index>=num.length){
			if(cnt!=M) return;
		}

		checked[index] = true;
		makeset(num, checked, index+1, cnt+1);

		checked[index] = false;
		makeset(num, checked, index+1, cnt);
	}
}

 

 

15651_N과 M (3) : 중복 순열

15651번: N과 M (3)

import java.io.BufferedReader;
import java.io.InputStreamReader;
import java.util.ArrayList;
import java.util.StringTokenizer;
import java.util.List;

public class Main {
	static int N;
	static int R;
	static StringBuilder sb = new StringBuilder();

	public static void main(String[] args) throws Exception{
		BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
		StringTokenizer st = new StringTokenizer(br.readLine());
		N = Integer.parseInt(st.nextToken());
		R = Integer.parseInt(st.nextToken());

		int[] num = new int[N];
		List<Integer> ans = new ArrayList<>();
		for(int i=0; i<num.length; i++){
			num[i] = i+1;
		}

		permutation(num, ans);
		System.out.print(sb);
	}
	private static void permutation(int[] num, List<Integer> ans) throws Exception{
		if(ans.size() == R){
			for(int i=0; i<ans.size(); i++){
				sb.append(ans.get(i)).append(" ");
			}
			sb.append('\n');
			return;
		}

		for(int i=0; i<num.length; i++){
			ans.add(num[i]);
			permutation(num, ans);
			ans.remove(ans.size()-1);
		}
	}
}

 

 

15652_N과 M (4) : 중복 조합

15652번: N과 M (4)

import java.io.BufferedReader;
import java.io.InputStreamReader;
import java.util.StringTokenizer;

public class Main {
	static int N;
	static int R;
	static StringBuilder sb = new StringBuilder();

	public static void main(String[] args) throws Exception{
		BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
		StringTokenizer st = new StringTokenizer(br.readLine());
		N = Integer.parseInt(st.nextToken());
		R = Integer.parseInt(st.nextToken());

		int[] num = new int[N];
		int[] ans = new int[R];
		for(int i=0; i<num.length; i++){
			num[i] = i+1;
		}

		combination(num, ans, 0, 0, 0);
		System.out.print(sb);
	}
	private static void combination(int[] num, int[] ans, int num_index, int ans_index, int cnt){
		if(num_index >= N)
			return;
		if(cnt == R){
			String str = "";
			for(int i=0; i<ans.length; i++){
				sb.append(ans[i]).append(" ");
			}
			sb.append('\n');
			return;
		}

		ans[ans_index] = num[num_index];
		combination(num, ans, num_index, ans_index+1, cnt+1);
		combination(num, ans, num_index+1, ans_index, cnt);
	}
}

 

 

 

 

 

 

 

 

순열 nPr

조합 nCr