Compilare: user.cpp: In function ‘bool dijkstra()’: user.cpp:36:13: warning: unused variable ‘a’ [-Wunused-variable] int a = pq.top().st, b = pq.top().nd; ^ user.cpp: In function ‘int main()’: user.cpp:104:35: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("fmcm.in", "r", stdin); ^ user.cpp:105:37: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("fmcm.out", "w", stdout); ^ user.cpp:107:40: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d %d %d %d",&n, &m, &s, &d); ^ user.cpp:112:31: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d %d", &x, &y); ^ user.cpp:113:48: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d %d", &cap[x][y], &cost[x][y]); ^