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i couldn't understand why um getting wa :( .here is my code..

#include<cstdio>
using namespace std;
int main()
{
long int shrt,tall,n=0,h,low,high,q,mid,num,a[50002],i,b[25001];
scanf("%ld", &num);
scanf("%ld", &a[n++]);
for(i=1;i<num;i++)
{
scanf("%ld", &h);
if(h != a[n-1])
a[n++]=h ...