Compilare: user.cpp: In function ‘void build_decomp()’: user.cpp:90:43: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int j = 0; j < chain[i].size(); ++ j) ^ user.cpp: In function ‘int main()’: user.cpp:100:40: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("heavypath.in", "r", stdin); ^ user.cpp:101:42: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("heavypath.out", "w", stdout); ^ user.cpp:105:27: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%i %i", &n, &m); ^ user.cpp:107:27: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%i", &v[i]); ^ user.cpp:110:31: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%i %i", &a, &b); ^ user.cpp:120:38: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%i %i %i", &t, &x, &y); ^