Compilare: user.cpp: In function ‘int main()’: user.cpp:23:32: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if (l<line[j].size() && k!=line[j][l]) dp[j][i]=(dp[j][i]+dp[k][i-1])%mod; ^ user.cpp:24:33: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if (l>=line[j].size()) dp[j][i]=(dp[j][i]+dp[k][i-1])%mod; ^ user.cpp:25:35: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] while (l<line[j].size() && k==line[j][l]) l++; ^ user.cpp:10:30: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("nrcuv.in","r",stdin); ^ user.cpp:11:32: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("nrcuv.out","w",stdout); ^ user.cpp:12:21: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d %d",&n,&m); gets(s); ^ user.cpp:12:30: warning: ignoring return value of ‘char* gets(char*)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d %d",&n,&m); gets(s); ^ user.cpp:14:25: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%c %c",&a,&b); gets(s); ^ user.cpp:14:34: warning: ignoring return value of ‘char* gets(char*)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%c %c",&a,&b); gets(s); ^ /tmp/ccgsULgl.o: In function `main': user.cpp:(.text.startup+0x72): warning: the `gets' function is dangerous and should not be used.