Compilare: main.cpp: In function 'int main()': main.cpp:146:22: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i = 0; i < solution.size(); ++i) ~~^~~~~~~~~~~~~~~~~ main.cpp:108:34: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result] freopen("apm.in", "r", stdin); ^ main.cpp:109:36: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result] freopen("apm.out", "w", stdout); ^ main.cpp:112:20: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result] scanf("%d", &n); ^ main.cpp:113:20: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result] scanf("%d", &m); ^ main.cpp:119:24: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result] scanf("%d", &x); ^ main.cpp:120:24: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result] scanf("%d", &y); ^ main.cpp:121:27: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result] scanf("%d", &cost); ^