Compilare: main.cpp: In function 'void prec(int)': main.cpp:56:23: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if(reVal[nod] == down[which[nod]].size()) down[which[nod]].push_back(0); ~~~~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~ main.cpp: In function 'int main()': main.cpp:126:35: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result] freopen("meow.in", "r", stdin); ^ main.cpp:127:37: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result] freopen("meow.out", "w", stdout); ^ main.cpp:129:32: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d%d", &n, &l, &q); ^ main.cpp:133:24: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result] scanf("%d", &x); ++x; ^ main.cpp:137:81: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result] for(int i = 1; i <= n ; ++i) scanf("%d", &val[i]), reVal[i] = l - val[i] + 1; ^ main.cpp:142:38: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result] scanf("%d", &newVal[nod]); ^