Compilare: main.cpp: In function 'int main()': main.cpp:18:14: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(i=1;i<=strlen(ch+1);i++) ~^~~~~~~~~~~~~~ main.cpp:12:31: warning: ignoring return value of 'int fscanf(FILE*, const char*, ...)', declared with attribute warn_unused_result [-Wunused-result] fscanf(fin,"%d%d\n",&n,&k); ^ main.cpp:13:27: warning: ignoring return value of 'char* fgets(char*, int, FILE*)', declared with attribute warn_unused_result [-Wunused-result] fgets(ch+1,600000,fin); ^