1335E2 - Three Blocks Palindrome (hard version)
In this problem, the solution outlined by the editorial is $$$O(n*200*200)$$$, here $$$N$$$ <= $$$200000$$$.
How is the solution able to pass with that time complexity on a constraint like this?
1335E2 - Three Blocks Palindrome (hard version)
In this problem, the solution outlined by the editorial is $$$O(n*200*200)$$$, here $$$N$$$ <= $$$200000$$$.
How is the solution able to pass with that time complexity on a constraint like this?
You pick a number (for first and third block) and iterate on its positions. Irregardless of the 'number' of numbers, there are only N positions in total to pick, thus the complexity is
O(N * 200)
. Of course you have to implement it in an appropriate way. Similar to how, when you DFS/BFS, you iterate on the children of a node, and you do it for every node! It seemsO(N^2)
but there are only N distinct nodes to visit in total.