LeetCode-in-Java
3584. Maximum Product of First and Last Elements of a Subsequence
Medium
You are given an integer array nums and an integer m.
Return the maximum product of the first and last elements of any **subsequences** of nums of size m.
Example 1:
Input: nums = [-1,-9,2,3,-2,-3,1], m = 1
Output: 81
Explanation:
The subsequence [-9] has the largest product of the first and last elements: -9 * -9 = 81. Therefore, the answer is 81.
Example 2:
Input: nums = [1,3,-5,5,6,-4], m = 3
Output: 20
Explanation:
The subsequence [-5, 6, -4] has the largest product of the first and last elements.
Example 3:
Input: nums = [2,-1,2,-6,5,2,-5,7], m = 2
Output: 35
Explanation:
The subsequence [5, 7] has the largest product of the first and last elements.
Constraints:
1 <= nums.length <= 105-105 <= nums[i] <= 1051 <= m <= nums.length
Solution
public class Solution {
public long maximumProduct(int[] nums, int m) {
long ma = nums[0];
long mi = nums[0];
long res = (long) nums[0] * nums[m - 1];
for (int i = m - 1; i < nums.length; ++i) {
ma = Math.max(ma, nums[i - m + 1]);
mi = Math.min(mi, nums[i - m + 1]);
res = Math.max(res, Math.max(mi * nums[i], ma * nums[i]));
}
return res;
}
}