Hi,

I need some advice regarding the following problem.

Problem:

Let A be an array of integers where x,y is an index 0 < x,y < |A|-1. Given x find y  s.t. A[y] = z and A[y] is the first z-value element encountered starting from A[x] to A[y] where x>y .
Example:

A=[2 3 43 12 46 7 8 9 90 4 34 4 4]
Given that  x = 5 the  A[5] = 7 and given that  z =4 then  y=9. The problem is how to do this in constant time. How to preprocess the array A so that when x=5 and z=4 are given as an input result that is received is y=9. Does anyone have any suggestions ??
Cheers Baxy

UPDATE:

YES that is it , you see you got it :) : 

"Given an array A, an index i, and a value v,
find the smallest index j such that j > i and A[j] == v"

[download]
dave_the_m

UPDATE:2

well if it is a CS homework than please provide a solution because then i missed that class and therefore i don't know the solution and am a bit puzzled on how to get one. Plus, I don't want to do a Spares table for this

In reply to Index finding problem by baxy77bax

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