An RLE compressed number is uncompressed as follows. Replace each occurrence of the substring "[k]c" (quotes for clarity), where k is a positive integer without leading zeroes and c is a single digit, with k consecutive occurrences of c. For example, "12[3]3[2]4[5]1" uncompresses to "123334411111". "123[2]3441[3]11" uncompresses to the same number.
Note that uncompression is not recursive; brackets are not allowed to be nested.
You are given two RLE compressed numbers a and b and String[] k. Uncompress a and b, and add them together. Return a int[], the ith element of which is the k[i]th digit of the sum. The 0th digit is the rightmost digit, the 1st digit is the next digit to the left, etc. If there are not enough digits, the corresponding element must be equal to 0.
