Compilare: user.cpp: In function ‘int main()’: user.cpp:81:37: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(right = 0; right < suf.size(); ++ right) { ^ user.cpp:42:9: warning: unused variable ‘len’ [-Wunused-variable] int len, x, y, i, left, right, sol; ^ user.cpp:40:37: 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:41:39: 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:44:31: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d%s", &n, &k, s); ^ user.cpp:42:36: warning: ‘sol’ may be used uninitialized in this function [-Wmaybe-uninitialized] int len, x, y, i, left, right, sol; ^