Compilare: main.cpp: In function 'int main()': main.cpp:41:24: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for ( i = 0; i < v[x].size(); i++ ) ~~^~~~~~~~~~~~~ main.cpp:17:34: warning: ignoring return value of 'int fscanf(FILE*, const char*, ...)', declared with attribute warn_unused_result [-Wunused-result] fscanf( fin, "%d%d", &n, &m ); ^ main.cpp:19:38: warning: ignoring return value of 'int fscanf(FILE*, const char*, ...)', declared with attribute warn_unused_result [-Wunused-result] fscanf( fin, "%d%d", &a, &b ); ^