Monday, August 31, 2020

LeetCode [1438] Longest Continuous Subarray With Absolute Diff Less Than or Equal to Limit

 1438. Longest Continuous Subarray With Absolute Diff Less Than or Equal to Limit

Medium

Given an array of integers nums and an integer limit, return the size of the longest non-empty subarray such that the absolute difference between any two elements of this subarray is less than or equal to limit.

 

Example 1:

Input: nums = [8,2,4,7], limit = 4
Output: 2 
Explanation: All subarrays are: 
[8] with maximum absolute diff |8-8| = 0 <= 4.
[8,2] with maximum absolute diff |8-2| = 6 > 4. 
[8,2,4] with maximum absolute diff |8-2| = 6 > 4.
[8,2,4,7] with maximum absolute diff |8-2| = 6 > 4.
[2] with maximum absolute diff |2-2| = 0 <= 4.
[2,4] with maximum absolute diff |2-4| = 2 <= 4.
[2,4,7] with maximum absolute diff |2-7| = 5 > 4.
[4] with maximum absolute diff |4-4| = 0 <= 4.
[4,7] with maximum absolute diff |4-7| = 3 <= 4.
[7] with maximum absolute diff |7-7| = 0 <= 4. 
Therefore, the size of the longest subarray is 2.

Example 2:

Input: nums = [10,1,2,4,7,2], limit = 5
Output: 4 
Explanation: The subarray [2,4,7,2] is the longest since the maximum absolute diff is |2-7| = 5 <= 5.

Example 3:

Input: nums = [4,2,2,2,4,4,2,2], limit = 0
Output: 3

 

Constraints:

  • 1 <= nums.length <= 10^5
  • 1 <= nums[i] <= 10^9
  • 0 <= limit <= 10^9
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class Solution {
    public int longestSubarray(int[] nums, int limit) {
        int n = nums.length, l = 0, r = 0, ret = 0;
        Deque<Integer> maxD = new ArrayDeque<>();
        Deque<Integer> minD = new ArrayDeque<>();
        while(r<n){
            while(!maxD.isEmpty() && nums[r]>maxD.peekLast()){
                maxD.pollLast();
            }
            while(!minD.isEmpty() && nums[r]<minD.peekLast()){
                minD.pollLast();
            }
            maxD.add(nums[r]);
            minD.add(nums[r]);
            while(maxD.peek()-minD.peek()>limit){
                if(maxD.peek()==nums[l]){
                    maxD.pop();
                }
                if(minD.peek()==nums[l]){
                    minD.pop();
                }
                l++;
            }
            ret = Math.max(ret, r-l+1);
            r++;
        }
        return ret;
    }
}

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