In the coding language you are most comfortable in describe what an array is, how you would reverse the output an array with a reversed order of elements and how you would replace a particular value that occurs.
Sigiloso
Array is a list for storing multiple values of a data type, can be multiple dimensions. Create a secondary array then using a for loop that iterates over all values set the new arrays values to the index of the the old index subtracted from the length of the original array. Include an if statement for the particular value within the for loop.