g1601_1700.s1695_maximum_erasure_value.Solution Maven / Gradle / Ivy

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Java-based LeetCode algorithm problem solutions, regularly updated

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package g1601_1700.s1695_maximum_erasure_value;

// #Medium #Array #Hash_Table #Sliding_Window #2022_04_13_Time_5_ms_(99.82%)_Space_53.3_MB_(92.02%)

/**
 * 1695 - Maximum Erasure Value\.
 *
 * Medium
 *
 * 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 <= 10⁵
 * *   1 <= nums[i] <= 10⁴
**/
public class Solution {
    public int maximumUniqueSubarray(int[] nums) {
        int ans = 0;
        int sum = 0;
        boolean[] seen = new boolean[10001];
        int j = 0;
        for (int num : nums) {
            while (seen[num]) {
                seen[nums[j]] = false;
                sum -= nums[j++];
            }
            seen[num] = true;
            sum += num;
            ans = Math.max(sum, ans);
        }
        return ans;
    }
}