Compilare: main.cpp: In function 'int main()': main.cpp:44:26: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i = 0; i < pos[val].size(); i ++) { ~~^~~~~~~~~~~~~~~~~ main.cpp:46:34: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int r = l; r - l <= 2 * pos[val].size() + 1 && r <= n; r ++) { ~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~