README_EN.md

2016. Maximum Difference Between Increasing Elements

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Description

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

Solutions

Python3

class Solution:
    def maximumDifference(self, nums: List[int]) -> int:
        mi = nums[0]
        ans, n = -1, len(nums)
        for i in range(1, n):
            if nums[i] > mi:
                ans = max(ans, nums[i] - mi)
            else:
                mi = nums[i]
        return ans

Java

class Solution {
    public int maximumDifference(int[] nums) {
        int mi = nums[0];
        int ans = -1;
        for (int i = 1; i < nums.length; ++i) {
            if (nums[i] > mi) {
                ans = Math.max(ans, nums[i] - mi);
            } else {
                mi = nums[i];
            }
        }
        return ans;
    }
}

TypeScript

function maximumDifference(nums: number[]): number {
    const n = nums.length;
    let min = nums[0];
    let res = -1;
    for (let i = 1; i < n; i++) {
        res = Math.max(res, nums[i] - min);
        min = Math.min(min, nums[i]);
    }
    return res === 0 ? -1 : res;
}

Rust

impl Solution {
    pub fn maximum_difference(nums: Vec<i32>) -> i32 {
        let mut min = nums[0];
        let mut res = -1;
        for i in 1..nums.len() {
            res = res.max(nums[i] - min);
            min = min.min(nums[i]);
        }
        match res {
            0 => -1,
            _ => res,
        }
    }
}

C++

class Solution {
public:
    int maximumDifference(vector<int>& nums) {
        int mi = nums[0];
        int ans = -1;
        for (int i = 1, n = nums.size(); i < n; ++i) {
            if (nums[i] > mi)
                ans = max(ans, nums[i] - mi);
            else
                mi = nums[i];
        }
        return ans;
    }
};

Go

func maximumDifference(nums []int) int {
	mi, ans := nums[0], -1
	for i, n := 1, len(nums); i < n; i++ {
		if nums[i] > mi {
			ans = max(ans, nums[i]-mi)
		} else {
			mi = nums[i]
		}
	}
	return ans
}

func max(a, b int) int {
	if a > b {
		return a
	}
	return b
}

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