Compilare: user.cpp: In function ‘int main()’: user.cpp:56:43: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen(inputFile.c_str(), "r", stdin); ^ user.cpp:57:45: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen(outputFile.c_str(), "w", stdout); ^ user.cpp:60:26: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d", &N, &M); ^ user.cpp:65:40: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%lld%lld", &X[i], &Y[i]); ^ user.cpp:85:26: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%lld", &x); ^ user.cpp:86:14: warning: ‘p’ may be used uninitialized in this function [-Wmaybe-uninitialized] i = p; ^