Description
You are given a 0-indexed integer array nums
.
Return the maximum value over all triplets of indices (i, j, k)
such that i < j < k
. If all such triplets have a negative value, return 0
.
The value of a triplet of indices (i, j, k)
is equal to (nums[i] - nums[j]) * nums[k]
.
Example 1:
Input: nums = [12,6,1,2,7] Output: 77 Explanation: The value of the triplet (0, 2, 4) is (nums[0] - nums[2]) * nums[4] = 77. It can be shown that there are no ordered triplets of indices with a value greater than 77.
Example 2:
Input: nums = [1,10,3,4,19] Output: 133 Explanation: The value of the triplet (1, 2, 4) is (nums[1] - nums[2]) * nums[4] = 133. It can be shown that there are no ordered triplets of indices with a value greater than 133.
Example 3:
Input: nums = [1,2,3] Output: 0 Explanation: The only ordered triplet of indices (0, 1, 2) has a negative value of (nums[0] - nums[1]) * nums[2] = -3. Hence, the answer would be 0.
Constraints:
3 <= nums.length <= 100
1 <= nums[i] <= 106
Solution
Python3
class Solution:
def maximumTripletValue(self, nums: List[int]) -> int:
N = len(nums)
res = 0
leftMax = [0] * N
rightMax = [0] * N
for i in range(N):
leftMax[i] = max(leftMax[max(i - 1, 0)], nums[i])
for i in range(N - 1, -1, -1):
rightMax[i] = max(rightMax[min(i + 1, N - 1)], nums[i])
for i in range(1, N - 1):
res = max(res, (leftMax[i - 1] - nums[i]) * rightMax[i + 1])
return res