#include <bitset> failed

Question

I want to use bitset in C++. So the time complexity is O(n). However, I failed to include. The compile error is "Line 7: 'bitset' was not declared in this scope".

So, are there any other way to solve this problem and the complexity is O(n);

Answer 1

#include <unordered_map> is what you want

try std::unordered_map<int, int>