[Math] baekjoon-21275

Author: Seogeurim

README.md

@@ -289,6 +289,7 @@
 |  #  |  ☆  | Problem                                        | Note   |
 | :-: | :-: | :--------------------------------------------- | :----- |
 | 01  |     | [Baekjoon-13458 시험 감독](./src/Math/P13458)    |        |
+| 02  |     | [Baekjoon-21275 폰 호석만](./src/Math/P21275)    | 완전탐색  |
 
 ## Number Theory
 

src/Math/P21275/Main.java

@@ -0,0 +1,65 @@
+package Math.P21275;
+
+import java.io.BufferedReader;
+import java.io.FileInputStream;
+import java.io.InputStreamReader;
+import java.util.StringTokenizer;
+
+public class Main {
+
+    static long X;
+    static int A, B;
+    static int[] n1, n2;
+
+    public static void main(String[] args) throws Exception {
+        System.setIn(new FileInputStream("src/Math/P21275/input.txt"));
+        BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
+        StringTokenizer st = new StringTokenizer(br.readLine());
+
+        String s1 = st.nextToken(), s2 = st.nextToken();
+
+        n1 = new int[s1.length()];
+        n2 = new int[s2.length()];
+        int A_min = 0, B_min = 0;
+
+        for (int i = 0, size = s1.length(); i < size; i++) {
+            char c = s1.charAt(size-i-1);
+            n1[i] = (c >= 'a') ? c - 'a' + 10 : c - '0';
+            A_min = Math.max(A_min, n1[i]+1);
+        }
+        for (int i = 0, size = s2.length(); i < size; i++) {
+            char c = s2.charAt(size-i-1);
+            n2[i] = (c >= 'a') ? c - 'a' + 10 : c - '0';
+            B_min = Math.max(B_min, n2[i]+1);
+        }
+
+        int cnt = 0;
+        loop:
+        for (int a = A_min; a <= 36; a++) {
+            long X1 = 0, a_ = 1;
+            for (int i = 0, size = s1.length(); i < size; i++) {
+                X1 += n1[i] * a_;
+                a_ *= a;
+            }
+            for (int b = B_min; b <= 36; b++) {
+                if (a == b) continue;
+                long X2 = 0, b_ = 1;
+                for (int i = 0, size = s2.length(); i < size; i++) {
+                    X2 += n2[i] * b_;
+                    b_ *= b;
+                }
+
+                if (X1 >= 0 && X1 == X2) {
+                    X = X1;
+                    A = a;
+                    B = b;
+                    if (++cnt > 1) break loop;
+                }
+            }
+        }
+
+        if (cnt == 1) System.out.println(X + " " + A + " " + B);
+        else if (cnt > 1) System.out.println("Multiple");
+        else System.out.println("Impossible");
+    }
+}

src/Math/P21275/README.md

@@ -0,0 +1,7 @@
+## [baekjoon-21275] 폰 호석만
+
+![image](https://user-images.githubusercontent.com/22045163/113019073-2b398080-91bc-11eb-9eae-a3a1001796d0.png)
+
+주어진 범위를 놓고 계산해보면 완전 탐색으로 풀 수 있는 문제이니 겁먹을 필요 없다.
+
+![image](https://user-images.githubusercontent.com/22045163/113019102-342a5200-91bc-11eb-9833-1f567cac7596.png)

src/Math/P21275/input.txt

@@ -0,0 +1 @@
+2222222222222222222222222222222222222222222222222222222222222222222222 8888888888888888888888888888888