salesman.cpp: In function 'int main()':
salesman.cpp:13:7: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
scanf("%d%d%d%d",&n,&u,&d,&s);
~~~~~^~~~~~~~~~~~~~~~~~~~~~~~
salesman.cpp:16:29: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
for (int i=1;i<=n;i++)scanf("%d%d%d",&a[i].day,&a[i].dis,&a[i].val);
~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~