Compilare: main.cpp: In function 'int main()': main.cpp:94:22: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if(vec[i].size() < k) { ~~~~~~~~~~~~~~^~~ main.cpp:105:27: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if(vec[cv].size() < k) { ~~~~~~~~~~~~~~~^~~ main.cpp:67:34: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result] freopen("zone2.in", "r", stdin); ^ main.cpp:68:36: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result] freopen("zone2.out", "w", stdout); ^ main.cpp:69:32: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d%d\n", &n, &m, &k); ^ main.cpp:73:23: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result] scanf("%c", &ch); ^ main.cpp:76:16: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result] scanf("\n"); ^