Check out example codes for "std map count vs find". It will help you in understanding the concepts better.

Code Example 1

In general, both count and find will use the container-specific lookup methods (tree traversal or hash table lookup), which are always fairly efficient. It's just that count has to continue iterating until the end of the equal-range, whereas find does not. Moreover, your code should document intent, so if you want to find something, use find.

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