Compilare: main.cpp: In function 'void solve()': main.cpp:154:9: warning: unused variable 'i' [-Wunused-variable] int i = 0; ^ main.cpp: In function 'int main()': main.cpp:198:30: warning: format '%d' expects argument of type 'int', but argument 2 has type 'std::vector<std::pair<int, int> >::size_type {aka long unsigned int}' [-Wformat=] printf("%d\n", ans.size()); ^ main.cpp:199:22: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i = 0; i < ans.size() ; ++i) ~~^~~~~~~~~~~~ main.cpp:167:35: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result] freopen("plan.in", "r", stdin); ^ main.cpp:168:37: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result] freopen("plan.out", "w", stdout); ^ main.cpp:172:26: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d", &n, &m); ^ main.cpp:175:30: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d", &x, &y); ^