title: BIT:Using a binary indexed tree?
body: <p>A binary indexed tree has very few or relatively no theory to study as compared to other data structures. The only place where it is taught succinctly <a href="http://community.topcoder.com/tc?module=Static&amp;d1=tutorials&amp;d2=binaryIndexedTrees">is the topcoder tutorial</a>. Although the tutorial is complete in all the explanations, I cannot understand that what is the intuition behind such a tree? And how to prove it's correctness?</p>
  
  <p>I presume that the proof is to complex to explain. So when using BIT, what approach do you follow?</p>