title: How to find the subarray that has sum closest to zero or a certain value t in O(nlogn)
body: <p>Actually it is the problem #10 of chapter 8 of Programming Pearls 2nd edition. It asked two questions: given an array A[] of integers(positive and nonpositive), how can you find a continuous subarray of A[] whose sum is closest to 0? Or closest to a certain value t? <br></p>
  
  <p>I can think of a way to solve the problem closest to 0. Calculate the prefix sum array S[], where S[i] = A[0]+A[1]+...+A[i]. And then sort this S according to the element value, along with its original index information kept, to find subarray sum closest to 0, just iterate the S array and do the diff of the two neighboring values and update the minimum absolute diff. <br></p>
  
  <p>Question is, what is the best way so solve second problem? Closest to a certain value t? Can anyone give a code or at least an algorithm? (If anyone has better solution to closest to zero problem, answers are welcome too)</p>