Several `coupons` are placed in a row, and to win the prize you need to pick **at least 2 coupons** of the same value. You can only pick consecutive coupons from the row. Each coupon costs 1 coin, find the minimum number of coins needed to obtain the prize or, -1 if it\'s not possible.\n\n**Example 1:**\n```\nInput: coupons = [5, 3, 4, 2, 3, 4, 5, 7]\nOutput: 4\nExplanation:\nBecause you can buy coupons with values [3, 4, 2, 3] or [4, 2, 3, 4]\n```\n\n**Example 2:**\n```\nInput: coupons = [3, 6, 1, 9]\nOutput: -1\n```\n\n<details> \n  <summary>Solution</summary>\n\nJava: https://leetcode.com/playground/AwwvRZcc\nTime complexity: `O(n)`.\nSpace complexity: `O(n)`.\n</details>

Several coupons are placed in a row, and to win the prize you need to pick at least 2 coupons of the same value. You can only pick consecutive coupons from the 