Compilare: user.cpp: In function ‘int main()’: user.cpp:33:38: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("rangemode.in", "r", stdin); ^ user.cpp:34:40: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("rangemode.out", "w", stdout); ^ user.cpp:36:24: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d", &N, &M); ^ user.cpp:38:23: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d", &v[i]); ^ user.cpp:40:38: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d", &q[i].st, &q[i].dr); ^ user.cpp:61:9: warning: ‘fmax’ may be used uninitialized in this function [-Wmaybe-uninitialized] if (f[v[i]] > fmax) { ^ user.cpp:69:30: warning: ‘index’ may be used uninitialized in this function [-Wmaybe-uninitialized] ans[q[j].index] = index; ^