Compilare: main.cpp: In function 'int main()': main.cpp:12:33: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result] freopen("logs.in", "r", stdin); ^ main.cpp:13:35: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result] freopen("logs.out", "w", stdout); ^ main.cpp:16:25: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d ", &n, &m); ^ main.cpp:21:30: warning: ignoring return value of 'char* fgets(char*, int, FILE*)', declared with attribute warn_unused_result [-Wunused-result] fgets(s + 1, MAXM, stdin); ^ In file included from /usr/include/stdio.h:936:0, from /usr/include/c++/6/cstdio:42, from /usr/include/x86_64-linux-gnu/c++/6/bits/stdc++.h:46, from main.cpp:1: In function 'char* fgets(char*, int, FILE*)', inlined from 'int main()' at main.cpp:21:30: /usr/include/x86_64-linux-gnu/bits/stdio2.h:261:58: warning: call to '__fgets_chk_warn' declared with attribute warning: fgets called with bigger size than length of destination buffer return __fgets_chk_warn (__s, __bos (__s), __n, __stream); ^