Compilare: main.cpp: In function 'void build_rmq()': main.cpp:82:21: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i = 0; i < euler.size(); i++) ~~^~~~~~~~~~~~~~ main.cpp:85:38: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int length = 1; (1 << length) <= euler.size(); length++) { ~~~~~~~~~~~~~~^~~~~~~~~~~~~~~ main.cpp:86:43: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i = 0; i + (1 << length) - 1 < euler.size(); i++) { ~~~~~~~~~~~~~~~~~~~~~~^~~~~~~~~~~~~~ main.cpp: In function 'int max_chain(int)': main.cpp:130:1: warning: no return statement in function returning non-void [-Wreturn-type] } ^ main.cpp: In function 'int main()': main.cpp:133:33: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result] freopen("apm2.in", "r", stdin); ^ main.cpp:134:35: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result] freopen("apm2.out", "w", stdout); ^ main.cpp:138:30: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d%d", &n, &m, &q); ^ main.cpp:142:35: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d%d", &u, &v, &cost); ^ main.cpp:172:26: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d", &u, &v); ^ main.cpp: In function 'void build_pow2()': main.cpp:99:13: warning: iteration 19998 invokes undefined behavior [-Waggressive-loop-optimizations] pow2[i] = pow2[i - 1]; ~~~~~~~~^~~~~~~~~~~~~ main.cpp:98:21: note: within this loop for (int i = 2; i <= 2 * MAX_N; i++) { ~~^~~~~~~~~~~~