3572. Maximize Y‑Sum by Picking a Triplet of Distinct X‑Values

Problem Link

Description

---

You are given two integer arrays x and y, each of length n. You must choose three distinct indices i, j, and k such that:

• x[i] != x[j]
• x[j] != x[k]
• x[k] != x[i]

Your goal is to maximize the value of y[i] + y[j] + y[k] under these conditions. Return the maximum possible sum that can be obtained by choosing such a triplet of indices.

If no such triplet exists, return -1.

 

Example 1:

Input: x = [1,2,1,3,2], y = [5,3,4,6,2]

Output: 14

Explanation:

• Choose i = 0 (x[i] = 1, y[i] = 5), j = 1 (x[j] = 2, y[j] = 3), k = 3 (x[k] = 3, y[k] = 6).
• All three values chosen from x are distinct. 5 + 3 + 6 = 14 is the maximum we can obtain. Hence, the output is 14.

Example 2:

Input: x = [1,2,1,2], y = [4,5,6,7]

Output: -1

Explanation:

• There are only two distinct values in x. Hence, the output is -1.

 

Constraints:

• n == x.length == y.length
• 3 <= n <= 105
• 1 <= x[i], y[i] <= 106

Solution

---

Python3

class Solution:
    def maxSumDistinctTriplet(self, A: List[int], B: List[int]) -> int:
        arr = []
 
        for a, b in zip(A, B):
            arr.append((b, a))
 
        arr.sort(key = lambda x : (-x[0], x[1]))
 
        used = set()
        curr = res = 0
        for b, a in arr:
            if a in used: continue
 
            used.add(a)
            res += b
            curr += 1
 
            if curr == 3: break
 
        if curr == 3: return res
        return -1