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  1. import java.util.Arrays;
  2. import java.util.Scanner;
  3. import java.util.regex.Matcher;
  4. import java.util.regex.Pattern;
  5.  
  6. class Alphametic
  7. {
  8.     public static void main(String[] args)
  9.     {
  10.         try (Scanner in = new Scanner(System.in))
  11.         {
  12.             while (in.hasNextLine())
  13.             {
  14.                 new Alphametic(in.nextLine()).print();
  15.             }
  16.         }
  17.     }
  18.  
  19.     private static Pattern pat = Pattern.compile("([0-9A-Z]+)([+-\\\\*])([0-9A-Z]+)=([0-9A-Z]+)");
  20.     private final String sa;
  21.     private final String sb;
  22.     private final String sc;
  23.     private final String op;
  24.     private final String[] st;
  25.     private final Op operator;
  26.     private final int e;
  27.  
  28.     private final int[] map = new int[256];
  29.     private final boolean[] used = new boolean[10];
  30.     private String[] result = new String[0];
  31.  
  32.     private Alphametic(String exp)
  33.     {
  34.         Matcher mat = pat.matcher(exp);
  35.         if (!mat.matches()) throw new IllegalArgumentException();
  36.  
  37.         this.sa = mat.group(1);
  38.         this.op = mat.group(2);
  39.         this.sb = mat.group(3);
  40.         this.sc = mat.group(4);
  41.         this.st = new String[] { sa, sb, sc };
  42.         switch(op)
  43.         {
  44.         case "+": operator = (a, b) -> a + b; break;
  45.         case "-": operator = (a, b) -> a - b; break;
  46.         case "*": operator = (a, b) -> a * b; break;
  47.         default: throw new IllegalArgumentException();
  48.         }
  49.  
  50.         // ここから
  51.         used[0] = true;
  52.         used[3] = true;
  53.         used[4] = true;
  54.         // ここまで追加
  55.  
  56.         for (int i = 0; i <= 9; i++) map['0' + i] = i;
  57.         for (int i = 'A'; i <= 'Z'; i++) map[i] = i;
  58.         e = Math.max(Math.max(sa.length(), sb.length()), sc.length()) * 3;
  59.         solve(0, new long[3], 1);
  60.     }
  61.  
  62.     private void solve(int p, long[] ls, long d)
  63.     {
  64.         if (p == e)
  65.         {
  66.             if (!operator.test(ls[0], ls[1], ls[2], Long.MAX_VALUE)) return;
  67.             for (String s : st) if (map[s.charAt(0)] <= 0) return;
  68.             result = Arrays.copyOf(result, result.length + 1);
  69.             result[result.length - 1] = String.format("%d%s%d=%d", ls[0], op, ls[1], ls[2]);
  70.             return;
  71.         }
  72.  
  73.         int i = p / 3;
  74.         int j = p % 3;
  75.         if (p > 0 && j == 0)
  76.         {
  77.             d *= 10;
  78.             if (!operator.test(ls[0], ls[1], ls[2], d)) return;
  79.         }
  80.  
  81.         int n = ch(st[j], i);
  82.         long l = ls[j];
  83.  
  84.         if (n >= 'A' && n <= 'Z')
  85.         {
  86.             for (int k = 0; k < 10; k++)
  87.             {
  88.                 if (used[k]) continue;
  89.                 used[k] = true;
  90.                 map[n] = k;
  91.                 ls[j] = l + k * d;
  92.                 solve(p + 1, ls, d);
  93.                 used[k] = false;
  94.             }
  95.             map[n] = n;
  96.         }
  97.         else
  98.         {
  99.             ls[j] += n * d;
  100.             solve(p + 1, ls, d);
  101.         }
  102.         ls[j] = l;
  103.     }
  104.  
  105.     private int ch(String s, int i)
  106.     {
  107.         return s.length() <= i ? 0 : map[s.charAt(s.length() - i - 1)];
  108.     }
  109.  
  110.     void print()
  111.     {
  112.         System.out.printf("%s%s%s=%s%n", sa, op, sb, sc);
  113.         for (String s : result) System.out.println(s);
  114.         System.out.println();
  115.     }
  116.  
  117.     private interface Op
  118.     {
  119.         long op(long a, long b);
  120.  
  121.         default boolean test(long a, long b, long c, long d)
  122.         {
  123.             return Math.abs(op(a, b) - c) % d == 0;
  124.         }
  125.     }
  126. }
Success #stdin #stdout 0.15s 4386816KB
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ABC4D-E3FG=77777
stdout
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ABC4D-E3FG=77777
87142-9365=77777
https://ideone.com/2chU62
language:
Java (HotSpot 12)
created:
6 years ago
visibility:
secret

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