Isn't the time complexity a little high, when `for (auto x : m) { ... }`?

[daidai21]

Isn't the time complexity a little high, when for (auto x : m) { ... }? One iteration calls fifo_map_compare n^2 times.

I think the time complexity of such a structure can be lower:

• one map: {Key, Value is pointer to node of queue}
• one queue: fifo, node{key, value}

For loop just iterates through the queue.

Looking forward to your reply!