1695. Maximum Erasure Value (M)

Maximum Erasure Value (M)

题目

You are given an array of positive integers nums and want to erase a subarray containing unique elements. The score you get by erasing the subarray is equal to the sum of its elements.

Return the maximum score you can get by erasing exactly one subarray.

An array b is called to be a subarray of a if it forms a contiguous subsequence of a, that is, if it is equal to a[l],a[l+1],...,a[r] for some (l,r).

Example 1:

Input: nums = [4,2,4,5,6]
Output: 17
Explanation: The optimal subarray here is [2,4,5,6].

Example 2:

Input: nums = [5,2,1,2,5,2,1,2,5]
Output: 8
Explanation: The optimal subarray here is [5,2,1] or [1,2,5]. 

Constraints:

• 1 <= nums.length <= 10^5
• 1 <= nums[i] <= 10^4

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题意

给定一个数组，在其中找到一个所有元素都不重复的子数组，使其和最大。

思路

滑动窗口，注意对已存在元素的判断即可。

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代码实现

Java

class Solution {
    public int maximumUniqueSubarray(int[] nums) {
        int ans = 0;
        int sum = 0;
        int left = 0;
        Set<Integer> set = new HashSet<>();

        for (int right = 0; right < nums.length; right++) {
            while (set.contains(nums[right])) {
                set.remove(nums[left]);
                sum -= nums[left++];
            }
            set.add(nums[right]);
            sum += nums[right];
            ans = Math.max(ans, sum);
        }

        return ans;
    }
}