ZCO15004 solution not accepted

My code is giving WA even though it gives correct answer in the sample cases.
Please help
My code:

#include <stdio.h>
#include <algorithm>
#define ll long long int
using namespace std;

int main()
{
    ll x_co=100000,y_co=500,n,max_v=0,grt=0;
    cin>>n;
    ll a[n][2];
    for(ll i=0;i<n;i++)
    {
        cin>>a[i][0];
        if(i!=0)
        {
            if(a[i][0]-a[i-1][0]>max_v)
            {
                max_v=a[i][0]-a[i-1][0];
            }
        }

cin>>a[i][1];
    }
    for(ll i=0;i<n;i++)
    {
        for(ll j=i+1;j<n;j++)
        {
            if(a[j][0]<a[i][0])
            {
                ll temp=a[j][0];
                a[j][0]=a[i][0];
                a[i][0]=temp;
            }
        }
    }
    grt=y_co*max_v;
    for(ll i=0;i<n;i++)
    {
        ll left=0,right=x_co;
        if(a[i][0]==a[i-1][0])
        {
            if(a[i][1]>a[i-1][1])
                continue;
        }
        if(a[i][0]==a[i+1][0])
        {
            if(a[i][1]>a[i+1][1])
                continue;
        }
        for(ll j=i-1;j>0;j--)
        {
            if(a[j][1]<a[i][1])
            {
                left=a[j][0];
                break;
            }
        }
        for(ll j=i+1;j<n;j++)
        {
            if(a[j][1]<a[i][1])
            {
                right=a[j][0];
                break;
            }
        }
        ll area=a[i][1]*(left-right);
        if(area>grt)
            grt=area;
    }
    if((a[0][0]*y_co)>grt)
        grt=a[0][0]*y_co;
    if(((x_co-a[n-1][0])*y_co)>grt)
        grt=(x_co-a[n-1][0])*y_co;
    cout<<grt;
    return 0;

}```

Please either format your code or link to your submission - the forum software has mangled it and it won’t compile! :slight_smile: