[solved] boj2661

HwangJinHa/BOJ/20231016 - 20231019 [ 화이팅 ]/boj2661_좋은수열.java

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+package study10월3주차목;
+
+import java.io.BufferedReader;
+import java.io.InputStreamReader;
+
+public class boj2661_좋은수열 {
+    static int[] arr;
+    public static void main(String[] args) throws Exception {
+        BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
+
+        arr = new int[Integer.parseInt(br.readLine())];
+        makearr(0);
+    }
+
+    private static void makearr(int depth) {
+        if (depth == arr.length) {
+            StringBuilder sb = new StringBuilder();
+            for (int i = 0; i < arr.length; i++) { sb.append(arr[i]); }
+            System.out.println(sb);
+            System.exit(0);
+        }
+
+        for (int i = 1; i <= 3; i++) {
+            arr[depth] = i;
+            if (check(depth)) {
+                makearr(depth + 1);
+            }
+        }
+    }
+
+    private static boolean check(int depth) {
+        int halfLen = (depth+1) / 2;
+        for (int checkLen = 1; checkLen <= halfLen; checkLen++) {
+            int start1 = depth - checkLen;
+            int end1 = start1 - checkLen;
+            int start2 = depth;
+            int end2 = start2 - checkLen;
+            if (end1 < -1)
+                break;
+            boolean isSame = true;
+            for (int i1 = start1, i2 = start2; i1 > end1; i1--, i2--) {
+                if (arr[i1] != arr[i2]) {
+                    isSame = false;
+                    break;
+                }
+            }
+            if (isSame)
+                return false;
+        }
+        return true;
+    }
+}