Compilare: user.cpp: In function ‘int solve(int, int)’: user.cpp:66:37: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int j=0;j<v[i].size();j++) ^ user.cpp: In function ‘int main()’: user.cpp:85:37: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int j=0;j<v[i].size();j++) ^ user.cpp:93:33: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int j=0;j<v[i].size();j++) ^ user.cpp: In function ‘char nextch()’: user.cpp:13:36: warning: ignoring return value of ‘size_t fread(void*, size_t, size_t, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] fread(buf, BUF_SIZE, 1, fi); ^