[20250914] BOJ / G5 / 0 만들기 / 김민진

zinnnn37/202509/14 BOJ G5 0 만들기.md

@@ -0,0 +1,99 @@
+```java
+package etc;
+
+import java.io.*;
+import java.util.ArrayList;
+import java.util.List;
+
+public class BJ_7490_0_만들기 {
+
+	private static final String OPS = " +-";
+
+	private static final BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
+	private static final BufferedWriter bw = new BufferedWriter(new OutputStreamWriter(System.out));
+	private static final StringBuilder  sb = new StringBuilder();
+
+	private static int    N;
+	private static char[] ops;
+
+	public static void main(String[] args) throws IOException {
+		int T = Integer.parseInt(br.readLine());
+		ops = new char[10];
+
+		while (T-- > 0) {
+			sol();
+			if (T > 0) {
+				sb.append("\n");
+			}
+		}
+		bw.write(sb.toString());
+		bw.flush();
+		bw.close();
+		br.close();
+	}
+
+	private static void sol() throws IOException {
+		N = Integer.parseInt(br.readLine());
+
+		for (int i = 0; i < 3; i++) {
+			char o = OPS.charAt(i);
+			ops[2] = o;
+			dfs(2);
+		}
+	}
+
+	private static void dfs(int num) {
+		if (num == N) {
+			if (isValid()) {
+				appendString();
+			}
+			return;
+		}
+
+		for (int i = 0; i < 3; i++) {
+			char o = OPS.charAt(i);
+			ops[num + 1] = o;
+			dfs(num + 1);
+		}
+	}
+
+	private static boolean isValid() {
+		List<Integer> nums = new ArrayList<>();
+
+		// 공백 처리
+		int idx = 0;
+		while (++idx <= N) {
+			int num = idx;
+			while (idx < N && ops[idx + 1] == ' ') {
+				idx++;
+				num = num * 10 + idx;
+			}
+			nums.add(num);
+		}
+
+		int res   = nums.get(0);
+		int opIdx = 2;
+
+		for (int i = 1; i < nums.size(); i++) {
+			// 공백 건너뛰기
+			while (opIdx <= N && ops[opIdx] == ' ') opIdx++;
+
+			if (ops[opIdx] == '+') {
+				res += nums.get(i);
+			} else {
+				res -= nums.get(i);
+			}
+			opIdx++;
+		}
+
+		return res == 0;
+	}
+
+	private static void appendString() {
+		for (int i = 1; i < N; i++) {
+			sb.append(i).append(ops[i + 1]);
+		}
+		sb.append(N).append('\n');
+	}
+}
+```