feat : 백준 문제 풀이

Author: cyeji

src/main/java/sgyj/backjun/yeji/Main1182.java

@@ -0,0 +1,41 @@
+package sgyj.backjun.yeji;
+
+import java.io.BufferedReader;
+import java.io.IOException;
+import java.io.InputStreamReader;
+import java.util.Arrays;
+
+// 부분수열의 합
+public class Main1182 {
+
+    private static int[] data;
+    private static int target;
+    private static int answer;
+    private static int N;
+
+    public static void main ( String[] args ) throws IOException {
+        BufferedReader br = new BufferedReader(new InputStreamReader(System.in) );
+        int[] input = Arrays.stream(br.readLine().split( " " )).mapToInt( Integer::parseInt ).toArray();
+        data = Arrays.stream( br.readLine().split( " " ) ).mapToInt( Integer::parseInt ).toArray();
+        target = input[1];
+        N = input[0];
+
+        dfs(0,0);
+
+        System.out.println(target == 0 ? answer - 1 : answer);
+    }
+
+    private static void dfs(int dep, int sum) {
+        if (dep == N) {
+            if (sum == target)
+                answer++;
+            return;
+        }
+
+        dfs(dep + 1, sum + data[dep]);
+        dfs(dep + 1, sum);
+    }
+
+
+
+}

src/main/java/sgyj/backjun/yeji/Main15649.java

@@ -0,0 +1,57 @@
+package sgyj.backjun.yeji;
+
+import java.io.BufferedReader;
+import java.io.IOException;
+import java.io.InputStreamReader;
+
+
+// N과 M (1)
+public class Main15649 {
+    // N : 1 부터 N까지의 수
+    // M : 조합의 갯수
+    private static boolean[] visited;
+    private static int[] data;
+    private static int N,M;
+
+    public static void solution(){
+        for(int i=1; i<=N; i++){
+            visited[i] = true;
+            data[0] = i;
+            dfs(1);
+            data[0] = 0;
+            visited[i] = false;
+        }
+    }
+
+    public static void dfs( int L){
+        if(L == M){
+            for(int i=0; i<data.length; i++){
+                if(data[i] != 0){
+                    System.out.print(data[i] + " ");
+                }
+            }
+            System.out.println();
+        }else{
+            for(int j=1; j<=N; j++){
+                if(!visited[j] ){
+                    visited[j] = true;
+                    data[L] = j;
+                    dfs(L+1);
+                    data[L] = 0;
+                    visited[j] = false;
+                }
+            }
+        }
+    }
+
+    public static void main ( String[] args ) throws IOException {
+        BufferedReader br = new BufferedReader( new InputStreamReader( System.in ) );
+        String[] s = br.readLine().split( " " );
+        N = Integer.parseInt( s[0] );
+        M = Integer.parseInt( s[1] );
+        visited = new boolean[N+1];
+        data = new int[N+1];
+        solution();
+    }
+
+}

src/main/java/sgyj/backjun/yeji/Main15650.java

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+package sgyj.backjun.yeji;
+
+import java.io.BufferedReader;
+import java.io.IOException;
+import java.io.InputStreamReader;
+import java.util.StringTokenizer;
+
+// N과M (2)
+public class Main15650 {
+
+    public static int[] arr;
+    public static int N, M;
+    public static StringBuilder sb = new StringBuilder();
+
+    public static void main(String[] args) throws IOException {
+
+        BufferedReader br = new BufferedReader( new InputStreamReader( System.in));
+        StringTokenizer st = new StringTokenizer( br.readLine());
+
+        N = Integer.parseInt(st.nextToken());
+        M = Integer.parseInt(st.nextToken());
+
+        arr = new int[M];
+
+        dfs(1, 0);
+        System.out.println(sb);
+
+    }
+
+    public static void dfs(int at, int depth) {
+
+        if (depth == M) {
+            for (int val : arr) {
+                sb.append(val).append(' ');
+            }
+            sb.append('\n');
+            return;
+        }
+
+        for (int i = at; i <= N; i++) {
+
+            arr[depth] = i;
+            dfs(i + 1, depth + 1);
+
+        }
+    }
+}

src/main/java/sgyj/backjun/yeji/Main2920.java

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+package sgyj.backjun.yeji;
+
+import java.io.BufferedReader;
+import java.io.IOException;
+import java.io.InputStreamReader;
+import java.util.Arrays;
+
+// 2920 : 음계
+public class Main2920 {
+
+    public static void main ( String[] args ) throws IOException {
+        BufferedReader br = new BufferedReader( new InputStreamReader( System.in ) );
+        int[] s = Arrays.stream( br.readLine().split( " " ) ).mapToInt( Integer::parseInt ).toArray();
+        int[] compare = Arrays.copyOf( s, s.length );
+        Arrays.sort( compare );
+        if(Arrays.compare( s,compare ) == 0){
+            System.out.println("ascending");
+        }else{
+            boolean flag = false;
+            for(int i=0; i<s.length; i++){
+                if(s[i] != compare[s.length-i-1]){
+                    System.out.println("mixed");
+                    flag = true;
+                    break;
+                }
+            }
+
+            if(!flag){
+                System.out.println("descending");
+            }
+        }
+
+    }
+}