I don't know what is right place to ask help regarding questions. I am solving http://mirror.codeforces.com/contest/1100/problem/B I read tutorial which solves it in O(m), but my solution is also of O(m), and I am getting TLE. Can someone suggest me the improvements? This is my solution:http://mirror.codeforces.com/contest/1100/submission/48488959
s=s+"0"
This runs in O(n), not O(1). You should replace it withs+="0"
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