Compilare: user.cpp: In function ‘int solve()’: user.cpp:28:38: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i = 0; i < a[x].size(); ++i) { ^ user.cpp:10:37: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d %d %d ", &n, &m, &source); ^ user.cpp:12:22: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d ", &D[i]); ^ user.cpp:15:39: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d %d %d ", &x, &y, &c); ^ user.cpp: In function ‘int main()’: user.cpp:43:39: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("distante.in", "r", stdin); ^ user.cpp:44:41: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("distante.out", "w", stdout); ^ user.cpp:45:22: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d\n", &t); ^