g2001_2100.s2016_maximum_difference_between_increasing_elements.Solution Maven / Gradle / Ivy

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package g2001_2100.s2016_maximum_difference_between_increasing_elements;

// #Easy #Array #2022_05_23_Time_0_ms_(100.00%)_Space_41.4_MB_(94.03%)

/**
 * 2016 - Maximum Difference Between Increasing Elements\.
 *
 * Easy
 *
 * 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
**/
public class Solution {
    public int maximumDifference(int[] nums) {
        int mini = nums[0];
        int ans = -1;
        for (int i = 0; i < nums.length - 1; i++) {
            if (nums[i] < mini) {
                mini = nums[i];
            }
            if (nums[i + 1] - mini > ans) {
                ans = nums[i + 1] - mini;
            }
        }
        return ans <= 0 ? -1 : ans;
    }
}