partition from programming pearls

Posted by davit-datuashvili on Stack Overflow See other posts from Stack Overflow or by davit-datuashvili
Published on 2010-05-17T13:16:28Z Indexed on 2010/05/17 13:20 UTC
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algorithms

hi suppose i have following array int a[]=new int[]{55,41,59,26,53,58,97,93}; i want to partition it around 55 so new array will be such } 41,26,53,55,59,58,93,93}; i have done such kinds of problems myself but this is from programming pearls and here code is like this we have some array[a..b] and given value t we write code following way

  int m=a-1;
  for i=[a..b]
     if ( array[i]<t)
 swap (++m;i);

where swap function exchange two element in array at indexes ++m and i, i have run this program and it showed me mistake Exception java.lang.NullPointerException can anybody help me?

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