## DEV Community

Abhishek Chaudhary

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# Maximum Difference Between Increasing Elements

Given a 0-indexed integer array `nums` of size `n`, find the maximum difference between `nums[i]` and `nums[j]` (i.e., `nums[j] - nums[i]`), such that `0 <= i < j < n` and `nums[i] < nums[j]`.

Return the maximum difference. If no such `i` and `j` exists, return `-1`.

Example 1:

Input: nums = [7,1,5,4]
Output: 4
Explanation:
The maximum difference occurs with i = 1 and j = 2, nums[j] - nums[i] = 5 - 1 = 4.
Note that with i = 1 and j = 0, the difference nums[j] - nums[i] = 7 - 1 = 6, but i > j, so it is not valid.

Example 2:

Input: nums = [9,4,3,2]
Output: -1
Explanation:
There is no i and j such that i < j and nums[i] < nums[j].

Example 3:

Input: nums = [1,5,2,10]
Output: 9
Explanation:
The maximum difference occurs with i = 0 and j = 3, nums[j] - nums[i] = 10 - 1 = 9.

Constraints:

• `n == nums.length`
• `2 <= n <= 1000`
• `1 <= nums[i] <= 109`

SOLUTION:

``````class Solution:
def maximumDifference(self, nums: List[int]) -> int:
mdiff = float('-inf')
minSoFar = nums[0]
for num in nums:
minSoFar = min(minSoFar, num)
mdiff = max(mdiff, num - minSoFar)
if mdiff > 0:
return mdiff
return -1
``````