solve: 프로그래머스 문제 풀이 - 11일차

Author: OhChangEun

2025-08-23/오창은/[solved] 백준_N과 M (2).java

@@ -0,0 +1,44 @@
+import java.io.*;
+
+public class Main {
+    static int N, M;
+    // static boolean[] visited;
+    static int[] selected;
+
+    public static void main(String[] args) throws IOException {
+        BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
+
+        String[] parts = br.readLine().split(" ");
+
+        N = Integer.parseInt(parts[0]);
+        M = Integer.parseInt(parts[1]);
+
+        // visited = new boolean[N + 1];
+        selected = new int[M];
+        dfs(1, 0);
+    }
+    public static void dfs(int curr, int depth) {
+        if (depth == M) {
+            for (int num: selected) {
+                System.out.print(num + " ");
+            }
+            System.out.println();
+            return;
+        }
+
+        for (int i=curr; i<=N; i++) {
+            selected[depth] = i;
+            dfs(i + 1, depth + 1);
+
+            // 항상 i보다 큰 숫자만 탐색하므로 visited가 필요가 없다
+            /*
+            if (!visited[i]) {
+                visited[i] = true;
+                selected[depth] = i;
+                dfs(i + 1, depth + 1);
+                visited[i] = false;
+            }
+             */
+        }
+    }
+}

2025-08-23/오창은/[solved] 백준_N과 M (4).java

@@ -0,0 +1,31 @@
+import java.io.*;
+
+public class Main {
+    static int N, M;
+    static int[] selected;
+
+    public static void main(String[] args) throws IOException {
+        BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
+
+        String[] parts = br.readLine().split(" ");
+
+        N = Integer.parseInt(parts[0]);
+        M = Integer.parseInt(parts[1]);
+
+        selected = new int[M];
+        dfs(1, 0);
+    }
+    public static void dfs(int curr, int depth) {
+        if (depth == M) {
+            for (int num: selected) {
+                System.out.print(num + " ");
+            }
+            System.out.println();
+            return;
+        }
+        for (int i=curr; i<=N; i++) {
+            selected[depth] = i;
+            dfs(i, depth + 1);
+        }
+    }
+}

2025-08-23/오창은/[solved] 백준_N과 M (5).java

@@ -0,0 +1,47 @@
+import java.io.*;
+import java.util.*;
+
+public class Main {
+    static int N, M;
+    static int[] inputs;
+    static boolean[] visited;
+    static int[] result;
+
+    public static void main(String[] args) throws IOException {
+        BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
+
+        String[] parts = br.readLine().split(" ");
+
+        N = Integer.parseInt(parts[0]);
+        M = Integer.parseInt(parts[1]);
+
+        inputs = new int[N];
+        visited = new boolean[N];
+        result = new int[M];
+        String[] inputParts = br.readLine().split(" ");
+        for (int i=0; i<N; i++) {
+            inputs[i] = Integer.parseInt(inputParts[i]);
+        }
+
+        Arrays.sort(inputs);
+        dfs(0, 0);
+    }
+    public static void dfs(int curr, int depth) {
+        if (depth == M) {
+            for (int num: result) {
+                System.out.print(num + " ");
+            }
+            System.out.println();
+            return;
+        }
+
+        for (int i=0; i<N; i++) {
+            if (!visited[i]) {
+                visited[i] = true;
+                result[depth] = inputs[i];
+                dfs(i, depth + 1);
+                visited[i] = false;
+            }
+        }
+    }
+}