Hill problem

hill.js

/*
Challenge 2: Hill

Given an array of integer elements

Your task is to
  * write a function that finds the minimum value X that makes possible the following: generate a new array that is sorted in strictly ascending order by increasing or decreasing each of the elements of the initial array with integer values in the [0, X] range.
        
    Example: Having the initial array [5, 4, 3, 2, 8] the minimum value for X is 3. Decrease the first element (5) by 3, decrease the second one (4) by 1, increase the third one (3) by 1, increase the forth one (2) by 3 and do nothing to the last one (8). In the end we obtain the array [2, 3, 4, 5, 8] which is sorted in strictly ascending order.
    
  * print the result X to the standard output (stdout)

Note that your function will receive the following arguments:
  * v which is the array of integers

Data constraints
  * numbers are in ascending order when arranged from the smallest to the largest number
  * strictly ascending order means that each element is greater than the preceding one (e.g. [1, 2, 2, 3] is NOT strictly ascending order)
  * the length of the array will not exceed 5000
  * the elements of any of the arrays are integer numbers in the [1, 2^31 -1] range

Efficiency constraints
  your function is expected to print the result in less than 2 seconds

Example
  Input v: 5, 4, 3, 2, 8
  Output: 3
 */
function hill(v) {
  var state = { off: null, max: null };
  for (var i=0; i<v.length; i++) {
    if (i === 0) {
      state.off = 0;
      state.max = v[i];
    } else {
      if (v[i] > state.max) {
        state.max = v[i];
      } else {
        var o = state.max - v[i];
        if (o > state.off) {
          state.off = o;
        } else if (o === state.off) {
          state.off = state.off + 1;
        } else {
          // keep same state.off
        }
        state.max = state.max;
      }
    }
  }
  console.log(state.off);
}

hill([5, 4, 3, 2, 8]);
hill([5, 4, 3, 4, 8]);
hill([3, 3, 2]);

Output:
3
2
2

hill([5,4,3,0,8])

returns 5

it is not correct.

My solution is:

function hill(v) {
    for (var i = 0; i < 10; i++) {
        var current = v[0] - i;
        for (var k = 1; k < v.length; k++) {
            current++;
            if (v[k] >= current) {
                if (v[k] - current > i) {
                    current = v[k] - i;
                }
            } else {
                if (current - v[k] > i) break;
            }
        }
        if (k === v.length) {
            console.log(i)
            return i;
        }
    }
}

returns 4 in this case

A different approach.

function hill(v) {
    var copy  = v.slice(0).sort();
    var max   = 0;

    for(var i = 0; i < v.length; i++) {
        var a = v[i];
        var b = copy[i];     

        // Difference
        if(a < b && ((b-a) > max)) {
            max = b - a;
        } else if(a-b > max) {
            max = a - b;
        }
    }

    return max;
}