10324 - Zeros and Ones - Java

 package org.goro.uva.m;  
 import java.io.*;  
 import java.util.*;  
 public class ZerosAndOnes {  
      public static void main(String[] args) throws Exception {  
           InputStreamReader isr = new InputStreamReader(System.in);  
           BufferedReader br = new BufferedReader(isr);  
           StringBuilder sb = new StringBuilder("");  
           int testCase = 1;  
           String line;  
           while ((line = br.readLine()) != null) {  
                sb.append("Case ").append(testCase).append(":\n");  
                testCase++;  
                int noOfCases = Integer.parseInt(br.readLine());  
                for (int j = 0; j < noOfCases; j++) {  
                     String[] str = br.readLine().split(" ");  
                     int val1 = Integer.parseInt(str[0]);  
                     int val2 = Integer.parseInt(str[1]);  
                     if (val1 > val2) {  
                          val1 ^= val2;  
                          val2 ^= val1;  
                          val1 ^= val2;  
                     }  
                     boolean isValid = true;  
                     if (val1 != val2) {  
                          for (int i = val1; i < val2; i++) {  
                               if (line.charAt(i) != line.charAt(i + 1)) {  
                                    isValid = false;  
                                    break;  
                               }  
                          }  
                     }  
                     if (isValid)  
                          sb.append("Yes\n");  
                     else   
                          sb.append("No\n");            
                }  
           }  
           System.out.print(sb);  
      }  
 }