Compilare: user.cpp: In function ‘void build_suffixArray()’: user.cpp:33:27: warning: suggest parentheses around ‘-’ inside ‘<<’ [-Wparentheses] if(j + (1<<cnt-1) < len) ^ user.cpp:34:46: warning: suggest parentheses around ‘-’ inside ‘<<’ [-Wparentheses] L[j].nr2=P[cnt-1][j + (1<<cnt-1)]; ^ user.cpp: In function ‘int main()’: user.cpp:61:35: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("substr.in","r",stdin); ^ user.cpp:62:37: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("substr.out","w",stdout); ^ user.cpp:63:29: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d %d\n",&len,&k); ^ user.cpp:64:14: warning: ignoring return value of ‘char* gets(char*)’, declared with attribute warn_unused_result [-Wunused-result] gets(str); ^ /tmp/cc3ouXTS.o: In function `main': user.cpp:(.text.startup+0x72): warning: the `gets' function is dangerous and should not be used.