Compilare: user.cpp: In function ‘int main()’: user.cpp:18:16: warning: format ‘%s’ expects argument of type ‘char*’, but argument 2 has type ‘char (*)[10005]’ [-Wformat=] scanf("%s", &s); ^ user.cpp:23:83: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] while(!st.empty() and ( s[i] - '0' > st.top() - '0' ) and ( N - i + st.size() > M ) ) { ^ user.cpp:26:18: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if(st.size() < M) { ^ user.cpp:9:35: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("alibaba.in", "r", stdin); ^ user.cpp:10:37: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("alibaba.out", "w", stdout); ^ user.cpp:13:24: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d %d", &N, &M); ^ user.cpp:18:17: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%s", &s); ^