Compilare: user.cpp: In function ‘long long int solve()’: user.cpp:65:19: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if (r - l + 1 > zero.size()) return -1; ~~~~~~~~~~^~~~~~~~~~~~~ user.cpp:62:9: warning: unused variable ‘i’ [-Wunused-variable] int i, j; ^ user.cpp:62:12: warning: unused variable ‘j’ [-Wunused-variable] int i, j; ^ user.cpp: In function ‘int main()’: user.cpp:107:19: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (i = 1; i < one.size(); i++) ~~^~~~~~~~~~~~ user.cpp:111:19: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (i = 1; i < zero.size(); i++) ~~^~~~~~~~~~~~~ user.cpp:91:35: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("copii3.in","r",stdin); ^ user.cpp:92:37: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("copii3.out","w",stdout); ^ user.cpp:94:37: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d\n%s", &n, &q, s + 1); ^ user.cpp:115:30: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d", &l, &r); ^