Compilare: main.cpp: In function 'int main()': main.cpp:28:21: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i = 1; i < a.size(); ++i) { ~~^~~~~~~~~~ main.cpp:32:20: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] while (right < a.size() && a[right - left] == a[right]) ~~~~~~^~~~~~~~~~ main.cpp:46:22: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] while (right < a.size() && a[right - left] == a[right]) ~~~~~~^~~~~~~~~~ main.cpp:55:21: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i = 1; i < a.size(); ++i) { ~~^~~~~~~~~~