Compilare: main.cpp: In function 'int main()': main.cpp:20:31: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i = 1, len = 0; i < A.length();){ ~~^~~~~~~~~~~~ main.cpp:37:29: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i = 0, j = 0; i < B.length();){ ~~^~~~~~~~~~~~ main.cpp:42:13: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if(j == A.length()){ ~~^~~~~~~~~~~~~ main.cpp:46:18: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] else if(i < B.length() && A[j] != B[i]){ ~~^~~~~~~~~~~~ main.cpp:54:22: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i = 0; i < result.size() && i < 1000; ++i) ~~^~~~~~~~~~~~~~~