Compilare: user.cpp: In function ‘void solve_cycle()’: user.cpp:83:32: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (i = 0; i < costs.size(); i++) { ^ user.cpp:96:36: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (i = 0; i + 1 < nodes.size(); i++) { ^ user.cpp: In function ‘int main()’: user.cpp:109:36: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("sistem3.in","r",stdin); ^ user.cpp:110:38: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("sistem3.out","w",stdout); ^ user.cpp:112:28: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d", &n, &mod); ^ user.cpp:114:36: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d%d", &x, &y, &w); ^ user.cpp:121:51: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] for (i = 1; i <= n; i++) scanf("%d", &data[i]); ^