Php-interview questions: use the least iteration to convert all elements of the array to the average value (balance)

Input: Array. all values are non-negative integers. target: convert each value of the array to the average value of all values, and use the least number of iterations transformation method: subtract one from each value, add one to the value next to the left or right. The first value of the array can only be 1 to the right, and the last value can be 1 to the left. during the transformation, all values in the number Group cannot be negative. Example 1: Input: [, 3] first: [, 3] [, 2] second: [, 2] Example 2, 1] [, 2] [, 3] [,] Example 3... php interview question algorithm array

Input: Array. all values are non-negative integers.
Objective: to convert each value of an array to the average value of all values, with the minimum number of iterations
Conversion Method: subtract one from a value to add one next to the value on the left or right. The first value of the array can only be 1 to the right, and the last value can be 1 to the left. during the transformation, all values in the number Group cannot be negative.
Example 1:
Input: [0, 3, 3]
First time: [1, 2, 3] [1, 3, 2]
Second: [2, 2, 2]
Example 2
[2, 4, 6, 2, 1]
[3, 3, 5, 2, 2]
[3, 3, 4, 2, 3]
[3, 3, 3, 3, 3]
Example 3
[1, 0, 7, 0]
[1, 1, 6, 0]
[2, 1, 5, 0]
[2, 2, 4, 0]
[2, 2, 3, 1]
[2, 2, 2, 2]
Is there any good algorithm to solve this problem? the example is not the only solution. The solution is implemented in php.