Compilare: user.cpp: In function ‘int main()’: user.cpp:14:37: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("maxsubsum.in", "r", stdin); ^ user.cpp:15:39: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("maxsubsum.out", "w", stdout); ^ user.cpp:16:23: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d", &n, &m); ^ user.cpp:19:21: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d", &A[i]); ^ user.cpp:41:21: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d", &B[i]); ^ user.cpp:12:37: warning: ‘beg’ may be used uninitialized in this function [-Wmaybe-uninitialized] int bestSum = -int(2e9), sum = 0, beg, end, idx; ^ user.cpp:12:42: warning: ‘end’ may be used uninitialized in this function [-Wmaybe-uninitialized] int bestSum = -int(2e9), sum = 0, beg, end, idx; ^