OCC '19 S4 - Playing with Numbers
View as PDFBack when was young, he enjoyed playing with sequences of numbers but there was always one problem that he could never solve. Now that he's older and has friends like you, he would like you to solve it for him.
Given an array  with 
 elements, he would like you to find the length of the longest non-decreasing subarray.
Since  was very smart when he was young, he would like for you to also answer this for  queries where in each query he will permanently change an element in the array to become 
.
Constraints
Subtask 1 [15%]
Subtask 2 [85%]
No additional constraints.
Input Specification
The first line will contain  and 
.
The second line will contain  integers containing the array 
.
The next  lines will contain a query of the form 
i x, stating that  has changed to 
.
Output Specification
Output  lines, the length of the longest non-decreasing subarray in 
 for the original array and for each query.
Sample Input 1
4 3
1 2 3 4
1 2
2 1
1 1
Sample Output 1
4
4
3
4
Explanation 1
In the original array, the longest non-decreasing subarray is 1 2 3 4.
After the first update, the array is now 2 2 3 4, and the longest non-decreasing subarray is 2 2 3 4.
After the second update, the array is now 2 1 3 4, and the longest non-decreasing subarray is 1 3 4.
After the third update, the array is now 1 1 3 4, and the longest non-decreasing subarray is 1 1 3 4.
Sample Input 2
9 3
1 2 3 4 0 1 2 3 4
5 -1
6 5
5 5
Sample Output 2
5
5
4
6
Explanation 2
In the original array, the longest non-decreasing subarray is 0 1 2 3 4.
After the first update, the array is now 1 2 3 4 -1 1 2 3 4, and the longest non-decreasing subarray is -1 1 2 3 4.
After the second update, the array is now 1 2 3 4 -1 5 2 3 4, and the longest non-decreasing subarray is 1 2 3 4.
After the third update, the array is now 1 2 3 4 5 5 2 3 4, and the longest non-decreasing subarray is 1 2 3 4 5 5.
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