Today I used two maps like that

map<pair<char,int>,int>mp1;

map<pair<char,int>,int>mp2;

It leaded to MLE-Memory Limit exceeded.

I guess some solutions with like this below got accepted-

map<int,vector<int>>mp1

map<int,vector<int>>mp2;

Then a question comes to my mind is there some anticpated benchmarks for using maps.How less complex it should be to avoid MLE?Is there some suggestions?