Amazon Online Assessment 2021 (OA) - Find Valid Discount Coupons

At Amazon's annual sale. employees are tasked with generating valid discount coupons for loyal customers. However, there are some used/invalid coupons in the mix and the challenge in this task is to determine whether a given discount coupon is valid or not.

The validity of a discount coupon is determined as follows:

  1. An empty discount coupon is valid.
  2. If a discount coupon A is valid, then a discount coupon C made by adding one character x to both the beginning of A and the end of A is also valid (i.e the discount coupon C = xAx is valid).
  3. If two discount coupons A and B are vand, then the concatenation of B and A is also valid (i.e the coupons AB and BA are both valid).

Given n discount coupons, each coupon consisting of only lowercase English characters, where the ith discount coupon is denoted discounts[i], determine if each discount coupon is valid or not. A valid coupon is denoted by 1 in the answer may while an invalid coupon is denoted by 0.


  • discounts: Array of discount coupons.


Array of integers, a valid coupon is denoted by 1 and an invalid coupon is denoted by 0.


Example 1:


1discounts = ['abba', 'abca']

Output: [1, 0]


'abba' is valid and 'abca' is invalid.

Try it yourself




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