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RabbitStepping(SRM 475 DIV1 Easy)

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1. import java.util.*;  
2. import java.lang.*;  
3. import java.math.*;  
4. public class RabbitStepping {  
5.  public double getExpected(String field, int r) {  
6.   int n=field.length();  
7.   int cnt=0, sum=0;  
8.   for(int i=0; i<1<<n; i++){  
9.    if(Integer.bitCount(i)==r){  
10.     int r1=0, r2=0;  
11.     for(int k=0; k<n; k++){  
12.      if((i>>k&1)==1){  
13.       if(k%2==0) r1++;  
14.       else  r2++;  
15.      }  
16.     }  
17.     cnt+=r1%2+r2%2;  
18.     sum++;  
19.    }  
20.   }  
21.   return (double)cnt/sum;  
22.  }  
23. }  
24.   
25.   
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27. // Powered by TZTester 1.01 [25-Feb-2003]  
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import java.util.*;
import java.lang.*;
import java.math.*;
public class RabbitStepping {
 public double getExpected(String field, int r) {
  int n=field.length();
  int cnt=0, sum=0;
  for(int i=0; i<1<<n; i++){
   if(Integer.bitCount(i)==r){
    int r1=0, r2=0;
    for(int k=0; k<n; k++){
     if((i>>k&1)==1){
      if(k%2==0) r1++;
      else  r2++;
     }
    }
    cnt+=r1%2+r2%2;
    sum++;
   }
  }
  return (double)cnt/sum;
 }
}


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