NEERC/headshot/headshot_re.java

   1 import java.io.*;
   2 import java.util.*;
   3
   4 /**
   5  * Solution for NEERC'2009 Problem H: Headshot
   6  * This solution checks correctness of the input.
   7  * @author Roman Elizarov
   8  */
   9 public class headshot_re {
  10
  11         public static void main(String[] args) throws Exception {
  12                 new headshot_re().go();
  13         }
  14
  15         void go() throws Exception {
  16                 read();
  17                 solve();
  18                 write();
  19         }
  20
  21         String s;
  22
  23         void read() throws Exception {
  24                 Scanner in = new Scanner(new File("headshot.in"));
  25                 in.useLocale(Locale.US);
  26                 s = in.next();
  27                 in.nextLine();
  28                 assert s.matches("[01]{2,100}");
  29                 assert s.contains("0");
  30                 in.close();
  31         }
  32
  33         enum Answer { EQUAL, ROTATE, SHOOT }
  34
  35         Answer a;
  36
  37         void solve() {
  38                 int p1 = count("01");
  39                 int q1 = count("0");
  40                 int p2 = count("1");
  41                 int q2 = s.length();
  42                 int diff = p1 * q2 - p2 * q1;
  43                 a = diff < 0 ? Answer.SHOOT : diff > 0 ? Answer.ROTATE : Answer.EQUAL;
  44         }
  45
  46         private int count(String t) {
  47                 int count = 0;
  48                 String ss = s + s.substring(0, t.length() - 1);
  49                 for (int i = 0; i < s.length(); i++) {
  50                     if (ss.substring(i, i + t.length()).equals(t))
  51                             count++;
  52                 }
  53                 return count;
  54         }
  55
  56         void write() throws Exception {
  57                 PrintWriter out = new PrintWriter("headshot.out");
  58                 out.println(a);
  59                 out.close();
  60         }
  61
  62 //----------------- just for validation ------------------
  63
  64         /**
  65          * Strict scanner to veryfy 100% correspondence between input files and input file format specification.
  66          * It is a drop-in replacement for {@link java.util.Scanner} that could be added to a soulution source
  67          * (cut-and-paste) without breaking its ability to work with {@link java.util.Scanner}.
  68          */
  69         public class Scanner {
  70                 private final BufferedReader in;
  71                 private String line = "";
  72                 private int pos;
  73                 private int lineNo;
  74                 private boolean localeset;
  75
  76                 public Scanner(File source) throws FileNotFoundException {
  77                         in = new BufferedReader(new FileReader(source));
  78                         nextLine();
  79                 }
  80
  81                 public void close() {
  82                         assert line == null : "Extra data at the end of file";
  83                         try {
  84                                 in.close();
  85                         } catch (IOException e) {
  86                                 throw new AssertionError("Failed to close with " + e);
  87                         }
  88                 }
  89
  90                 public void nextLine() {
  91                         assert line != null : "EOF";
  92                         assert pos == line.length() : "Extra characters on line " + lineNo;
  93                         try {
  94                                 line = in.readLine();
  95                         } catch (IOException e) {
  96                                 throw new AssertionError("Failed to read line with " + e);
  97                         }
  98                         pos = 0;
  99                         lineNo++;
 100                 }
 101
 102                 public String next() {
 103                         assert line != null : "EOF";
 104                         assert line.length() > 0 : "Empty line " + lineNo;
 105                         if (pos == 0)
 106                                 assert line.charAt(0) > ' ' : "Line " + lineNo + " starts with whitespace";
 107                         else {
 108                                 assert pos < line.length() : "Line " + lineNo + " is over";
 109                                 assert line.charAt(pos) == ' ' : "Wrong whitespace on line " + lineNo;
 110                                 pos++;
 111                                 assert pos < line.length() : "Line " + lineNo + " is over";
 112                                 assert line.charAt(0) > ' ' : "Line " + lineNo + " has double whitespace";
 113                         }
 114                         StringBuilder sb = new StringBuilder();
 115                         while (pos < line.length() && line.charAt(pos) > ' ')
 116                                 sb.append(line.charAt(pos++));
 117                         return sb.toString();
 118                 }
 119
 120                 public int nextInt() {
 121                         String s = next();
 122                         assert s.length() == 1 || s.charAt(0) != '0' : "Extra leading zero in number " + s + " on line " + lineNo;
 123                         assert s.charAt(0) != '+' : "Extra leading '+' in number " + s + " on line " + lineNo;
 124                         try {
 125                                 return Integer.parseInt(s);
 126                         } catch (NumberFormatException e) {
 127                                 throw new AssertionError("Malformed number " + s + " on line " + lineNo);
 128                         }
 129                 }
 130
 131                 public double nextDouble() {
 132                         assert localeset : "Locale must be set with useLocale(Locale.US)";
 133                         String s = next();
 134                         assert s.length() == 1 || s.startsWith("0.") || s.charAt(0) != '0' : "Extra leading zero in number " + s + " on line " + lineNo;
 135                         assert s.charAt(0) != '+' : "Extra leading '+' in number " + s + " on line " + lineNo;
 136                         try {
 137                                 return Double.parseDouble(s);
 138                         } catch (NumberFormatException e) {
 139                                 throw new AssertionError("Malformed number " + s + " on line " + lineNo);
 140                         }
 141                 }
 142
 143                 public void useLocale(Locale locale) {
 144                         assert locale == Locale.US;
 145                         localeset = true;
 146                 }
 147         }
 148 }