Compilare: main.c: In function 'main': main.c:24:5: warning: implicit declaration of function 'qsort' [-Wimplicit-function-declaration] qsort((void*)p,m,4,F); ^~~~~ main.c:21:5: warning: ignoring return value of 'freopen', declared with attribute warn_unused_result [-Wunused-result] freopen("apm.in","r",stdin),freopen("apm.out","w",stdout),scanf("%d%d",&n,&m); ^~~~~~~~~~~~~~~~~~~~~~~~~~~ main.c:21:33: warning: ignoring return value of 'freopen', declared with attribute warn_unused_result [-Wunused-result] freopen("apm.in","r",stdin),freopen("apm.out","w",stdout),scanf("%d%d",&n,&m); ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~ main.c:21:63: warning: ignoring return value of 'scanf', declared with attribute warn_unused_result [-Wunused-result] freopen("apm.in","r",stdin),freopen("apm.out","w",stdout),scanf("%d%d",&n,&m); ^~~~~~~~~~~~~~~~~~~ main.c:23:9: warning: ignoring return value of 'scanf', declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d%d",x+i,y+i,c+i),d[i]=p[i]=i; ^~~~~~~~~~~~~~~~~~~~~~~~~~~