Compilare: main.cpp: In function 'int main()': main.cpp:36:25: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if(s.size() < k) continue ; ~~~~~~~~~^~~ main.cpp:19:36: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result] freopen("drept.in", "r", stdin); ^ main.cpp:20:38: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result] freopen("drept.out", "w", stdout); ^ main.cpp:22:26: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d", &n, &k); ^ main.cpp:24:40: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d", &a[i].x, &a[i].y); ^