Compilare: user.cpp: In function ‘int main()’: user.cpp:54:40: 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:55:42: 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:57:27: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d %d", &n, &m); ^ user.cpp:59:27: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d", &a[i]); ^ user.cpp:63:27: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d", &b[i]); ^ user.cpp: In function ‘std::pair<long long int, long long int> ssm(int*, int)’: user.cpp:33:32: warning: ‘f’ may be used uninitialized in this function [-Wmaybe-uninitialized] return pair<ll, ll>(sol, f - s + 1); ^ user.cpp:33:32: warning: ‘s’ may be used uninitialized in this function [-Wmaybe-uninitialized] user.cpp: In function ‘int main()’: user.cpp:33:32: warning: ‘s’ may be used uninitialized in this function [-Wmaybe-uninitialized] user.cpp:15:31: note: ‘s’ was declared here long long sol = -INF; int s, f; ^ user.cpp:33:32: warning: ‘f’ may be used uninitialized in this function [-Wmaybe-uninitialized] return pair<ll, ll>(sol, f - s + 1); ^ user.cpp:15:34: note: ‘f’ was declared here long long sol = -INF; int s, f; ^