Compilare: main.cpp: In function 'bool exist(std::vector<std::pair<int, int> >&, int, int)': main.cpp:23:16: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(i = 0; i < v.size(); i++) ~~^~~~~~~~~~ main.cpp: In function 'char bkt(std::vector<std::pair<int, int> >&)': main.cpp:34:15: warning: unused variable 'p' [-Wunused-variable] int i, j, p, ni, nj, n = v.size(), dx, dy; ^ main.cpp: In function 'int main()': main.cpp:92:37: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result] freopen("immortal.in", "r", stdin); ^ main.cpp:93:39: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result] freopen("immortal.out", "w", stdout); ^ main.cpp:96:30: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d%d", &n, &m, &k); ^ main.cpp:98:26: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d", &x, &y); ^