Given an array, find the length of the longest increasing subarray (contiguous elements) such that it is possible to change at most one number (change one number to any integer you want) from the sequence to make the sequence strictly increasing.
Input : 6 7 2 3 1 5 10 Output : 5 Explanation : Here, we can choose subarray 2, 3, 1, 5, 10 and by changing its 3rd element (that is 1) to 4, it will become increasing sequence. Input : 2 10 10 Output : 2 Explanation : Here, we can choose subarray 10, 10 and by changing its 2nd element (that is 10) to 11, it will become increasing sequence.
Step 1: We first compute longest increasing subarray ending at an index for every index in given array. We store these values in l.
Step 2: Then calculate longest increasing subarray starting at an index for every index in given array. We store these values in r.
Step 3: Update the answer ans = max ( ans, l[i-1] + r[i+1] + 1), when a[i-1] + 1 < a[i+1].
Below is the implementation of the above approach:
This article is contributed by Abhishek Sharma. If you like GeeksforGeeks and would like to contribute, you can also write an article using contribute.geeksforgeeks.org or mail your article to email@example.com. See your article appearing on the GeeksforGeeks main page and help other Geeks.
Please write comments if you find anything incorrect, or you want to share more information about the topic discussed above.
- Largest Sum Contiguous Subarray
- Find the Minimum length Unsorted Subarray, sorting which makes the complete array sorted
- Longest Increasing Subsequence Size (N log N)
- Maximum Length Bitonic Subarray | Set 1 (O(n) time and O(n) space)
- Find the maximum element in an array which is first increasing and then decreasing
- Maximum Sum Increasing Subsequence | DP-14
- Find subarray with given sum | Set 1 (Nonnegative Numbers)
- Largest subarray with equal number of 0s and 1s
- Maximum Product Subarray
- XOR of all subarray XORs | Set 2
- Maximum circular subarray sum
- Construction of Longest Increasing Subsequence (N log N)
- Maximum Subarray Sum using Divide and Conquer algorithm
- Find the Increasing subsequence of length three with maximum product
- Longest Arithmetic Progression | DP-35
Improved By : sanjeev2552