Compilare: main.cpp: In function 'int BFS()': main.cpp:31:22: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(i = 0; i < a[x].size(); ++i) ~~^~~~~~~~~~~~~ main.cpp: In function 'void Path(int, int)': main.cpp:57:22: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(i = 0; i < a[x].size(); ++i) ~~^~~~~~~~~~~~~ main.cpp: In function 'int main()': main.cpp:86:22: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(i = 0; i < a[N].size(); ++i) ~~^~~~~~~~~~~~~ main.cpp:75:30: 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:78:40: warning: ignoring return value of 'int fscanf(FILE*, const char*, ...)', declared with attribute warn_unused_result [-Wunused-result] fscanf(fin,"%d %d %d",&x,&y,&z); ^